{{Infobox U.S. County
| county = DeKalb County
| state = Tennessee
| seal = 
| seallink =

| founded = 
| seat = Smithville
| largest city = Smithville
| area_total_sq_mi = 329
| area_total_km2 = 852
| area_land_sq_mi = 305
| area_land_km2 = 789
| area_water_sq_mi = 24
| area_water_km2 = 63
| area percentage = 7.42%
| census yr = 2000
| pop = 17423
| density_sq_mi = 57
| density_km2 = 22
| time zone = Central
| UTC offset = -6
| DST offset= -5
| footnotes = 
| web = 
| ex image     = Dekalb_county_courthouse.jpg
| ex image cap = Dekalb County Courthouse in Smithville, Tennessee
|}}'''DeKalb County''' is a county located in the U.S. state of Tennessee.  As of 2000, the population is 17,423.  The 2005 Census Estimate placed the population at 18,254  [http://www.census.gov/popest/counties/tables/CO-EST2005-01-47.xls].

==Geography==
According to the U.S. Census Bureau, the county has a total area of 329&nbsp;square miles (852&nbsp;km²), of which, 305&nbsp;square miles (789&nbsp;km²) of it is land and 24&nbsp;square miles (63&nbsp;km²) of it (7.42%) is water.

===Adjacent counties===
*Putnam County (northeast)
*White County (east)
*Warren County (south)
*Cannon County (southwest)
*Wilson County (west)
*Smith County (northwest)

==Demographics==
As of the White, 1.43% Black or African American, 0.28% Native American, 0.14% Asian, 0.02% Pacific Islander, 1.62% from other races, and 0.94% from two or more races.  3.63% of the population were Hispanic or Latino of any race.

thumb|left|150px|Age pyramid DeKalb County<ref>Based on [[2000 census data</ref>]]
There were 6,984 households out of which 30.10% had children under the age of 18 living with them, 56.10% were married couples living together, 11.10% had a female householder with no husband present, and 28.60% were non-families. 25.50% of all households were made up of individuals and 10.70% had someone living alone who was 65 years of age or older.  The average household size was 2.45 and the average family size was 2.90.

In the county, the population was spread out with 23.30% under the age of 18, 8.50% from 18 to 24, 29.30% from 25 to 44, 24.60% from 45 to 64, and 14.30% who were 65 years of age or older.  The median age was 38 years. For every 100 females there were 97.70 males.  For every 100 females age 18 and over, there were 94.90 males.

{{Infobox County (Vereinigte Staaten)
|BUNDESSTAAT=Tennessee
|BUNDESSTAAT-LINK=Tennessee
|COUNTY=DeKalb County
|SITZ=Smithville
|GRUENDUNG=11. Dezember 1837
|GEBILDET_AUS=Jackson County<br/ >Warren County<br/ >White County<br/ >Wilson County
|EINWOHNER=18254
|STAND_EINWOHNER=2005
|FLAECHE=852
|WASSER_FLAECHE=<!--TM_WF-->

|VORWAHL=001 615
|ADRESSE=County Courthouse<br/ >1 Public Square<br/ >Smithville, TN 37166-1443
|WEBSITE=www.smithvilletn.com/government
}}
'''DeKalb County''' ist ein County im US-Bundesstaat Vereinigten Staaten von Amerika. Der Sitz der County-Verwaltung (Smithville.

==Geografie==
Das County liegt nordöstlich des geographischen Zentrums von Tennessee und hat eine Fläche von 852&nbsp;km², wovon 63&nbsp;km² Wasserfläche sind. Es grenzt im Uhrzeigersinn an die Countys: Putnam County, White County, Warren County, Wilson County und Smith County.

==Geschichte==
DeKalb County wurde am 11. Dezember 1837 aus Teilen des Cannon-, Jackson-, Warren-, White- und Wilson County gebildet. Benannt wurde es nach Johann DeKalb, einem deutsch-amerikanischen Generalmajor der Amerikanischen Unabhängigkeitskrieg.

==Bevölkerungsentwicklung==
{| style="border-style:solid;border-width:1px;border-color:#808080;background-color:#EFEFEF" cellspacing="2" cellpadding="2" width="200px"
|- bgcolor="#EFEFEF"
! 1980
! 1990
! 2000
! 2005
|- align="center" valign="top" bgcolor="#BFEFFF"
| align="left" | 13.549
| align="left" | 14.360
| align="left" | 17.423
| align="left" | 18.254
|}