{| border=1 align=right cellpadding=4 cellspacing=0 width=300 style="margin: 0.5em 0 1em 1em; background: #f9f9f9; border: 1px #aaaaaa solid; border-collapse: collapse; font-size: 95%;"
|+<big><big>'''Bulgaria'''</big></big>
|-
| style="background:#efefef;" align="center" colspan="2" |
{| border="0" cellpadding="2" cellspacing="0"
|-
| align="center" width="140px" | 300px|center|Map of Bulgaria.
|}
|-
| '''| [[Europe
|-
| '''| [[Balkan Peninsula
|-
| '''Geographic coordinates''' || 
|- 
| '''Area'''<br>&nbsp;- Total <br>&nbsp;- Water
| Ranked 104<br>110,910 km²<br> 360 km²
|-
| '''Coastline''' || 354 km 
|-
| '''Land boundaries''' || 1,808 km
|-
| '''Countries bordered''' || Romania 608 km, Serbia 318 km, Republic of Macedonia 148 km, Greece 494 km, Turkey 240 km
|-
| '''Maritime claims''' || 200 nm
|-
| '''Highest point''' || Musala, 2,925 m&nbsp;
|-
| '''Lowest point''' || Black Sea, 0 m
|-
| '''Longest river''' || Iskar River, 368 km 
|-
| '''Largest lake''' || Lake Burgas 27 km² 
|-
| '''Land Use'''<br>&nbsp;- Arable land<br>&nbsp;- Permanent<br>&nbsp;&nbsp;&nbsp;crops<br>&nbsp;- Forests and<br>&nbsp;&nbsp;&nbsp;woodlands<br>&nbsp;- Other ||<br>29,9 %<br><br>1,9 %<br><br>34 %<br>34,2 % (2005 est.)
|- 
| '''| [[Temperate to subtropical
|-
| '''| [[plains, mountains, hills
|-
| '''Natural resources''' ||  iron ore, manganese, zinc, copper, gold, lead, potash, silver, timber, wildlife, coal, hydropower
|-
| '''Natural hazards''' || earthquakes (in certain areas)
|-
| '''Environmental issues''' || air and water pollution
|}

'''Bulgaria''' is a country situated in south-eastern Europe, bordering Romania, Serbia, the Republic of Macedonia, Greece, Turkey and the Black Sea. Its northern border with Romania follows the Danube river until Silistra. The land area of Bulgaria is 110,550 square kilometers, slightly larger than that of Iceland or the U.S. state of Tennessee. The country is situated on the west coast of the Black Sea, with Romania to the north, Greece and Turkey to the south, and Serbia to the west. Considering its small size, Bulgaria has a great variety of topographical features. Even within small parts of the country, the land may be divided into plains, plateaus, hills, mountains, basins, gorges, and deep river valleys. The geographic center of Bulgaria is located in Uzana.

'''Geographic coordinates:'''

==Boundaries==
Although external historical events often changed Bulgaria's national boundaries in its first century of existence, natural terrain features defined most boundaries after 1944, and no significant group of people suffered serious economic hardship because of border delineation. Postwar Bulgaria contained a large percentage of the ethnic Macedonia—which it shares with both Republic of Macedonia and Greece—is less than just because of the ethnic connection between Macedonians and Bulgarians.

Bulgaria has a total border of about 2,264 km. Rivers account for about 680 km and the Black Sea coast for 400 km; the southern and western borders are mainly defined by ridges in high terrain. The western and northern boundaries are shared with Serbia and Romania, respectively, and the Black Sea coastline constitutes the entire eastern border. The Romanian border follows the Danube for 464 km from the northwestern corner of the country to the city of Silistra and then cuts to the east-southeast for 136 km. The Danube, with steep bluffs on the Bulgarian side and a wide area of swamps and marshes on the Romanian side, is one of the most effective river boundaries in Europe. The line through Dobruja is arbitrary and was redrawn several times according to international treaties. In that process, most inhabitants with strong national preferences resettled in the country of their choice. Borders to the south are with Greece and Turkey, the border with Greece being 491 kilometres long, and the Turkish border having a length of 240 kilometres.

==Topography==

The Danubian Plain, Rilo-Rhodope Massif. The easternmost sections near the Black Sea are hilly, but they gradually gain height to the west until the westernmost part of the country is entirely high ground.

Table showing the distribution of the hight zones in Bulgaria<ref>География на България, 2002, с.30</ref>:
{|  border="1" cellpadding="4" cellspacing="0" style="margin: 10px 0 10px 25px; background: #f9f9f9; border: 1px #AAA solid; border-collapse: collapse; font-size: 85%; float: center;"
|- BGCOLOR="#EFEFEF" STYLE="border-bottom: 2px solid gray;"
! Height zones
! Height (m)
! Area (km²) 
! Area (%)
|-
| Lowlands || 0-200 || 34,858 || 31,42
|-
| Hills || 200-600 || 45,516 || 41,00
|-
| Low mountains || 600-1000 || 16,918 || 15,24
|-
| Medium-high mountains || 1000-1600 || 10,904 || 9,82
|-
| High mountains || 1600-2925 || 2,798 || 2,52
|-
|}
More than two-thirds of the country is plains, plateaus, or hilly land at an altitude less than 600 m. Plains (below 200 m) make up 31 % of the land, plateaus and hills (200 to 600 m) 41 %, low mountains (600 to 1,000 m) 10 %, medium-sized mountains (1,000 to 1,500 m) 10 %, and high mountains (over 1,500 m) 3 %. The average altitude in Bulgaria is 470 m.

The contemporary relief of the country is a result of continuous magmatic, sedimentary and metamorphic rocks of different origin, age and composition. Their formation began more than 500 million years ago during the Precambrian and continues till now. The Bulgarian lands were often submerged by ancient seas and lakes, some land layers rose others sank. Volcanic eruptions were common both on land and in the water basins.

===Danubian plain===

thumb|right|200px|View of Zlataritsa, Veliko Turnovo Region
The Danubian Plain extends from the western borders to the Black Sea. It encompasses the area between the Danube River, which forms most of the country's northern border, and Stara Planina to the south. It covers the Moesian plate. As a result of the rock weathering processes the relief is uneaven with flat rising grounds along the valleys and plateaus to the east. The plateau slopes gently from cliffs along the river, then it abuts into the low northern mountains of the Balkan range. The highest point is Tarnov Dyal (502 m) in the Shumen Plateau. The valleys of Vit and Yantra divide the Danubian plain into three parts - western, central and eastern. The altitude rises from west to east. To the north the plain has steep shores along the Danube or forms fertile alluvial plains (Vidinska, Chernopolska, Belenska, Pobrezhie, Aidemirska). 

Hilly heights and plateaus are typical for the topography of plain. Most of the heights and all plateaus are situated into the eastern parts. There are 14 basalt mounds between Svishtov and the village of Dragomirovo.  

===Stara Planina===
200px|thumb|right|The [[Belogradchik Rocks in western Stara Planina]]
The southern edge of the Danubian Plain blends into the foothills of Stara Planina, sometimes thought of as the Bulgarian part of the Carpathian Mountains. The Carpathians resemble a reversed S as they run eastward from the Czech Republic and Slovakia across the northern portion of Romania, swinging southward to the middle of Romania and then running westward, where they are known as the Transylvanian Alps. The mountains turn eastward again at the Iron Gate, a gorge of the Danube River at the Romanian-Serbian border. At that point, they become Stara Planina of Bulgaria.

Stara Planina originates at the Timok Valley in Serbia and run southward towards the Sofia Basin in west central Bulgaria. From there they run east to the Black Sea. The Balkans are about 600 km long and 30 to 50 km wide. They retain their height well into central Bulgaria, where Botev Peak, the highest point in the Balkan Mountains, rises to about 2,376 m. The range then continues at lower altitude to the cliffs of the Black Sea. Through most of Bulgaria, the Balkans form the watershed from which rivers drain north to the Danube River or south to the Aegean Sea. Some smaller rivers in the east drain directly to the Black Sea. The Sredna Gora is a narrow ridge about 160 km long and 1,600 m high, running east to west parallel to the Balkans. Nested between both ranges is the Rose Valley, famous for rose oil used in perfume and liqueurs.

===Subbalkan Valleys and Thracian Plain===

The southern slopes of the Balkan Mountains and the Sredna Gora give way to the Thracian Plain and the Sofia Basin. Roughly triangular in shape, the Thracian Plain originates at a point east of the mountains near Sofia and broadens eastward to the Black Sea. It includes the Maritsa valley and the lowlands that extend from the river to the Black Sea. Like the Danubian Plateau, much of the Thracian Plain is somewhat hilly and not a true plain. Most of its terrain is moderate enough to cultivate.

The largest basin in Bulgaria is the Roman times, determining the strategic significance of the Balkan Peninsula. Bulgaria's largest cities were founded on this route. Paradoxically, although the mountains made many Bulgarian villages and towns relatively inaccessible, Bulgaria has always been susceptible to invasion because no natural obstacle blocked the route through Sofia.

===Rilo-Rhodope massif===

thumb|200px|Winter landscape in the [[Vitosha Mountains, with the Rila Mountains in the background]]Relatively high mountains occupy the area between the Thracian Plain and Sofia Basin and the Greek border to the south. The western parts consist of three ranges: the Rila Mountains further south, and the Mount Vihren, at 2,915 meters the second-highest peak in Bulgaria. Further east are the extensive Rhodope Mountains.
800px|thumb|center|Panorama of Pirin
200px|thumb|left|Maljovitsa summit in Rila
200px|thumb|right|View from the Rhodoppi mountains
A significant part of Bulgaria's land is prone to earthquakes. Two especially sensitive areas are the borders of the North Bulgarian Swell (rounded elevation), the center of which is in the Gorna Oryahovitsa area in north-central Bulgaria, and the West Rhodopes Vault, a wide area extending through the Rila and northern Pirin regions to Plovdiv in south-central Bulgaria. Especially strong tremors also occur along diagonal lines running between Skopje in the Republic of Macedonia and Razgrad in northeast Bulgaria, and from Albania eastward across the southern third of Bulgaria through Plovdiv. Sixteen major earthquakes struck Bulgaria between 1900 and 1986, the last two in Strazhitsa on the Skopje-Razgrad fault line. Together the two quakes damaged over 16,000 buildings, half of them severely. One village was almost completely leveled, others badly damaged. Many inhabitants were still living in temporary housing four years later.

==Drainage==
thumb|200px|right|Tevno Vasilashko Lake in Pirin mountain in Bulgaria
<!-- Image with unknown copyright status removed: 200px|thumb|right|The highest waterfall in the Balkans in central Stara Planina -->
The Balkan Mountains divide Bulgaria into two nearly equal drainage systems. The larger system drains northward to the Black Sea, mainly by way of the Danube River. This system includes the entire Danubian Plateau and a stretch of land running forty-eight to eighty kilometers inland from the coastline. The second system drains the Thracian Plain and most of the higher lands of the south and southwest to the Aegean Sea. Although only the Danube is navigable, many of the other rivers and streams in Bulgaria have a high potential for the production of hydroelectric power and are sources of irrigation water.

Of the Danube's Bulgarian tributaries, all but the Iskar River rise in the Balkan Mountains. The Iskur flows northward to the Danube from its origin in the Rila Mountains, passing through Sofia's eastern suburbs and through a Balkan Mountain valley.

The Danube gets slightly more than 4 % of its total volume from its Bulgarian tributaries. As it flows along the northern border, the Danube averages 1.6 to 2.4 kilometers in width. The river's highest water levels usually occur during June floods; it is frozen over an average of forty days per year.

Several major rivers flow directly to the Mesta (which separate the Pirin Mountains from the main Rhodopes ranges) are the next largest Bulgarian rivers flowing to the Aegean. Struma and Mesta reach the sea through Greece.

==Climate==
Considering its small area, Bulgaria has an unusually variable and complex climate. The country lies between the strongly contrasting continental and Mediterranean climatic zones. Bulgarian mountains and valleys act as barriers or channels for air masses, causing sharp contrasts in weather over relatively short distances. The continental zone is slightly larger, because continental air masses flow easily into the unobstructed Danubian Plain. The continental influence, stronger during the winter, produces abundant snowfall; the Mediterranean influence increases during the summer and produces hot, dry weather. The barrier effect of the Balkan Mountains is felt throughout the country: on the average, northern Bulgaria is about one degree cooler and receives about 192 more millimetres of rain than southern Bulgaria. Because the Black Sea is too small to be a primary influence over much of the country's weather, it only affects the immediate area along its coastline.

The Balkan Mountains are the northern boundary of the area in which continental air masses circulate freely. The Rhodope Mountains mark the southern limits of domination by Mediterranean weather systems. The area between, which includes the Thracian Plain, is influenced by a combination of the two systems, with the continental predominating. This combination produces a plains climate resembling that of the Corn Belt in the United States, with long summers and high humidity. The climate in this region is generally more severe than that of other parts of Europe in the same latitude. Because it is a transitional area, average temperatures and precipitation are erratic and may vary widely from year to year.

Average precipitation in Bulgaria is about 630 millimetres per year. Dobruja in the northeast, the Black Sea coastal area, and parts of the Thracian Plain usually receive less than 500 millimetres. The remainder of the Thracian Plain and the Danubian Plateau get less than the country average; the Thracian Plain is often subject to summer droughts. Higher elevations, which receive the most rainfall in the country, may average over 2,540 millimeters per year.

The many valley basins scattered through the uplands have temperature inversions resulting in stagnant air. Sofia is located in such a basin, but its elevation (about 530 meters) tends to moderate summer temperature and relieve oppressive high humidity. Sofia also is sheltered from the northern European winds by the mountains that surround its troughlike basin. Temperatures in Sofia average -2°C in January and about 28°C in August. The city's rainfall is near the country average, and the overall climate is pleasant.

The coastal climate is moderated by the Black Sea, but strong winds and violent local storms are frequent during the winter. Winters along the Danube River are bitterly cold, while sheltered valleys opening to the south along the Greek and Turkish borders may be as mild as areas along the Mediterranean or Aegean coasts.

{{Infobox Géographique (pays)
| carte=Bu-map_FR.jpg
| continent=Europe
| région=Balkans
| coordonnées=43° 00' N, 25° 00' E
| rang=112
| superficie=110 910
| terres=99,5
| eau=0,5
| côtes=354
| frontières=Total 1 808 km :<br />Macédoine 148&nbsp;km, Roumanie 608&nbsp;km, Serbie 318&nbsp;km, Turquie 240&nbsp;km
| altitude maximale=Mousala (2 925 m)
| altitude minimale=Mer Noire (0 m)
| fleuve=Danube
| lac=?
}}
La Bulgarie est un pays situé dans le sud-est de l'Europe. Elle est bordée par la Roumanie au nord (608 km de frontière), la Serbie (318 km) et la république de Macédoine (148 km) à l'ouest, la Grèce (494 km) et la Turquie (240 km) au sud et la mer Noire à l'est. La majeure partie de sa frontière septentrionale avec la Roumanie est délimitée par le Danube jusqu'à Silistra. La superficie du pays est de 110&nbsp;550 km² (un peu plus grand que l'Islande). Bien que de taille assez réduite, la Bulgarie jouit d'une grande variété de paysages. Même dans des zones géographiques restreintes on trouve souvent superposés plaine, plateau, colline, montagne, vallée de rivière encaissée, bassin et gorge. Le centre géographique de la Bulgarie est situé à Uzana. 

== Topographie ==

La principale caractéristique de la Bulgarie est sa division en bandes de montagnes et de plaines orientées Est-Ouest. Du Nord au Sud se succèdent le massif des Balkans (Stara planina), la massif des Rhodopes. La partie Est, près de la mer Noire, est constituée de collines qui gagnent progressivement en hauteur en allant vers l'Ouest. La partie Ouest du pays est constituée uniquement de montagnes.

Plus des deux tiers du pays, constitués de plaines plateaux et  collines, se situent à une altitude inférieure à 600 mètres. Les plaines (moins de 200 mètres d'altitude) représentent 31 % de la surface du pays, les plateaux (entre 200 et 600 mètres) 41 % de la surface, les montagnes de faible élévation (entre 600 et 1&nbsp;000 mètres) 10 %, les montagnes  moyennes (entre 1&nbsp;000 et 1&nbsp;500 mètres) 10 % et les montagnes élevées (plus de 1&nbsp;500 mètres) 3 %. L'altitude moyenne de la Bulgarie est de 470 mètres.

Le '''Plateau Danubien''' s'étend des frontières ouest à la mer Noire. Il comprend une zone délimitée au Nord par le Danube et au Sud par le massif des Balkans. Le plateau est bordé de falaises le long du Danube et s'arrête le long d'une bande de montagnes d'une altitude de 750 à 900 mètres. Le plateau est une zone fertile, parcourue de collines; c'est le grenier du pays.

Le Sud du plateau s'arrête au pied du Massif des Carpathes. Le massif des Carpathes dessine un S couché : courant vers l'Est en République Tchèque et en Slovaquie et la partie Nord de la Roumanie, il se tourne vers le Sud au milieu de la Roumanie puis continue vers l'Ouest ou il est connu sous l'appellation d'Alpes carpathiennes. Le massif se tourne à nouveau vers l'Est au niveau des Portes de Fer, une gorge sur le Danube située à la frontière entre la Roumanie et la Serbie. A cet endroit il devient le Stara Planina de Bulgarie.

Le massif de Stara Planina débute à la vallée de Timok en Serbie et court vers le Sud jusqu'au bassin de Sofia au Centre Ouest de la Bulgarie. Il prend ensuite une direction Est jusqu'à la mer Noire. Le massif fait 600 km  de long pour une largeur comprise entre 30 et 50 km. Les plus hauts sommets se trouvent au Centre de la Bulgarie avec Le Pic Botev qui culmine à 2&nbsp;376 m. La chaine continue ensuite vers l'Est avec des sommets moins élevés jusqu'au falaises de la mer Noire. Dans pratiquement toute la Bulgarie, le massif des Balkans définit la limite de partage des eaux entre le bassin du Danube et celui qui draine les eaux vers la mer Égée. Certaines petites rivières à l'Est se déversent directement dans la mer Noire. Le massif de Sredna Gora est une chaîne étroite de 160 km de long et 1&nbsp;600 mètres de haut qui court d'Est en Ouest parallèlement au massif des Balkans. La vallée des Roses située entre ces deux massifs est connue pour son essence de rose utilisée dans la parfumerie et les liqueurs.

Les versants Sud du massif des Balkans et de Sredna Gora débouchent sur la '''plaine de Thrace''' et le bassin de Sofia. Approximativement de forme triangulaire, la plaine de Thrace débute à l'est des montagnes dominant Sofia et va vers l'Est en s'élargissant jusqu'à la mer Noire. Elle inclut la vallée de Maritasa et les terres basses qui vont de la rivière à la mer Noire. Comme le plateau danubien, la plaine de Thrace est en partie vallonnée. La majorité des terres sont cependant cultivables.

Le plus grand bassin de Bulgarie est le '''Bassin de Sofia'''. Large de 24 km et long de 96 km, le bassin est occupé par la capitale de la Bulgarie et la région limitrophe. La route qui suit les vallées et les bassins depuis Belgrade jusqu'à Istanbul (anciennement Constantinople) et qui passe par le Bassin de Sofia a une importance historique qui remonte à l'époque romaine et qui a contribué au rôle stratégique de la péninsule des Balkans. Les plus grandes villes de Bulgarie se situent sur cette route. De manière paradoxale, bien que de nombreuses montagnes rendent les villages et les villes de Bulgarie relativement inaccessibles, la Bulgarie a été régulièrement menacée d'invasions à cause de cette route passant par Sofia dépourvue d'obstacles naturels. 

Des montagnes relativement hautes occupent la zone située entre le Bassin de Sofia, la Plaine de Thrace et la frontière avec la Grèce au Sud : les montagnes de Vistosha au sud de Sofia, le Massif de Rila plus loin au Sud et le massif de Pirin au Sud Ouest de la Bulgarie. Ces montagnes constituent les paysages les plus saisissants de Bulgarie et de toute la Mont Musala (2&nbsp;925 mètres) plus haut sommet des pays balkans. Une douzaine d'autres sommets dans le même massif culminent à plus de 2&nbsp;600 mètres. Les plus hautes montagnes se caractérisent par  des sommets rocheux et des lacs situés au dessus de la limite arbustive. Les sommets moins élevés sont couverts de prairies alpestres qui donnent à la chaîne une image de paysage verdoyant. La chaîne des Pirin est caractérisé par des sommets et des pentes rocheuses. Son plus haut sommet est le mont Vihren ,la deuxième plus haute montagne de Bulgarie. Plus à l'Ouest se trouve le vaste massif des Rhodopes.

Une partie importante de la Bulgarie est sujette aux secousses sismiques. Deux zones sont particulièrement concernées : 
* le Nord de l'ondulation de Bulgarie du Nord centrée sur la région de Gorna Oryahovitsa au Centre Nord de la Bulgarie
* le plissement Ouest des Rhodopes, une vaste zone s'étendant depuis les régions de Rila et du Nord Piron jusqu'à Plovdiv dans le Centre Sud de la Bulgarie

Des séismes particulièrement importants ont lieu le long de la diagonale qui va de Skopje en République de Macédoine jusqu'à Razgrad dans le Nord Est de la Bulgarie et sur la diagonale qui va de l'Albanie vers le tiers Sud de la Bulgarie en passant par Plovdiv. 16 séismes majeurs ont frappé la Bulgarie entre 1900 et 1966; les deux derniers se sont produits à Strazhitsa sur la ligne de faille Skopje-Razgrad. Ces deux séismes ont endommagés 16&nbsp;000 bâtiments, la moitié d'entre eux de manière importante. Un village a été complètement anéanti, d'autres endommagés gravement. Beaucoup d'habitants vivaient encore des abris provisoires quatre ans plus tard.

== Réseau hydrographique ==
thumb|right|300px|Carte détaillée de la Bulgarie

Les montagnes des Balkans divisent la Bulgarie en 2 bassins hydrographiques. Le plus important se déverse dans la mer Noire en faisant converger la majorité des rivières vers le Danube. Ce bassin inclut tout le plateau danubien et une bande de terrain le long de la mer Noire d'une largeur de 40 à 80 km. Le deuxième bassin draine les eaux de la plaine de Thrace et de la plupart des terres hautes situées à l'Ouest et au Sud de la Bulgarie vers la mer Égée. Seul le Danube est navigable; de nombreuses rivières en Bulgarie disposent d'un potentiel important pour la production d'énergie hydroélectrique. 