卡斯特縣 (南達科他州)

{{Infobox U.S. county
| state = South Dakota
| county = Custer County
| county_zh = 卡斯特縣
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| area_total_km2 =
| area_total_sq_mi = 1559
| area_land_km2 =
| area_land_sq_mi = 1558
| area_water_km2 =
| area_water_sq_mi = 1
| area percentage = 0.09%
| census yr = 2000
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| pop = 7275
| population_density_km2 = 2
| population_density_sq_mi = 5
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| coordinates = {{coord|{}|0|N|{}|0|W|type:adm2nd|display=title,inline}}
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卡斯特縣（）是美國南達科他州西南部的一個縣，西鄰懷俄明州。面積4,038平方公里。根據美國2000年人口普查，共有人口7,275人。縣治卡斯特（Custer）。

成立於1875年。縣名紀念南北戰爭騎兵司令喬治·阿姆斯壯·卡斯特。