List of Counties in South Dakota
| County | FIPS Code | County Seat | Established in | Population | Area (sq mi) | Area (km2) |
| Aurora County | 3 | Plankinton | 1881 | 2,710 | 708 | 1,834 |
| Beadle County | 5 | Huron | 1879 | 17,398 | 1,259 | 3,261 |
| Bennett County | 7 | Martin | 1909 | 3,431 | 1,185 | 3,069 |
| Bon Homme County | 9 | Tyndall | 1862 | 7,070 | 563 | 1,458 |
| Brookings County | 11 | Brookings | 1862 | 31,965 | 794 | 2,056 |
| Brown County | 13 | Aberdeen | 1879 | 36,531 | 1,713 | 4,437 |
| Brule County | 15 | Chamberlain | 1875 | 5,255 | 819 | 2,121 |
| Buffalo County | 17 | Gann Valley | 1873 | 1,912 | 471 | 1,220 |
| Butte County | 19 | Belle Fourche | 1883 | 10,110 | 2,249 | 5,825 |
| Campbell County | 21 | Mound City | 1873 | 1,466 | 736 | 1,906 |
| Charles Mix County | 23 | Lake Andes | 1862 | 9,129 | 1,098 | 2,844 |
| Clark County | 25 | Clark | 1873 | 3,691 | 958 | 2,481 |
| Clay County | 27 | Vermillion | 1862 | 13,864 | 412 | 1,067 |
| Codington County | 29 | Watertown | 1877 | 27,227 | 688 | 1,782 |
| Corson County | 31 | McIntosh | 1909 | 4,050 | 2,473 | 6,405 |
| Custer County | 33 | Custer | 1875 | 8,216 | 1,558 | 4,035 |
| Davison County | 35 | Mitchell | 1873 | 19,504 | 436 | 1,129 |
| Day County | 37 | Webster | 1879 | 5,710 | 1,029 | 2,665 |
| Deuel County | 39 | Clear Lake | 1862 | 4,364 | 624 | 1,616 |
| Dewey County | 41 | Timber Lake | 1873 | 5,301 | 2,303 | 5,965 |
| Douglas County | 43 | Armour | 1873 | 3,002 | 434 | 1,124 |
| Edmunds County | 45 | Ipswich | 1873 | 4,071 | 1,146 | 2,968 |
| Fall River County | 47 | Hot Springs | 1883 | 7,094 | 1,740 | 4,507 |
| Faulk County | 49 | Faulkton | 1873 | 2,364 | 1,000 | 2,590 |
| Grant County | 51 | Milbank | 1873 | 7,356 | 682 | 1,766 |
| Gregory County | 53 | Burke | 1862 | 4,271 | 1,016 | 2,631 |
| Haakon County | 55 | Philip | 1914 | 1,937 | 1,813 | 4,696 |
| Hamlin County | 57 | Hayti | 1873 | 5,903 | 511 | 1,323 |
| Hand County | 59 | Miller | 1873 | 3,431 | 1,437 | 3,722 |
| Hanson County | 61 | Alexandria | 1873 | 3,331 | 435 | 1,127 |
| Harding County | 63 | Buffalo | 1909 | 1,255 | 2,671 | 6,918 |
| Hughes County | 65 | Pierre | 1880 | 17,022 | 741 | 1,919 |
| Hutchinson County | 67 | Olivet | 1862 | 7,343 | 813 | 2,106 |
| Hyde County | 69 | Highmore | 1873 | 1,420 | 861 | 2,230 |
| Jackson County | 71 | Kadoka | 1914 | 3,031 | 1,869 | 4,841 |
| Jerauld County | 73 | Wessington Springs | 1883 | 2,070 | 530 | 1,373 |
| Jones County | 75 | Murdo | 1916 | 1,006 | 971 | 2,515 |
| Kingsbury County | 77 | De Smet | 1873 | 5,148 | 838 | 2,170 |
| Lake County | 79 | Madison | 1873 | 11,200 | 563 | 1,458 |
| Lawrence County | 81 | Deadwood | 1875 | 24,097 | 800 | 2,072 |
| Lincoln County | 83 | Canton | 1867 | 44,828 | 578 | 1,497 |
| Lyman County | 85 | Kennebec | 1873 | 3,755 | 1,640 | 4,248 |
| Marshall County | 91 | Britton | 1885 | 4,656 | 839 | 2,173 |
| McCook County | 87 | Salem | 1873 | 5,618 | 575 | 1,489 |
| McPherson County | 89 | Leola | 1873 | 2,459 | 1,137 | 2,945 |
| Meade County | 93 | Sturgis | 1889 | 25,434 | 3,471 | 8,990 |
| Mellette County | 95 | White River | 1909 | 2,048 | 1,307 | 3,385 |
| Miner County | 97 | Howard | 1873 | 2,389 | 570 | 1,476 |
| Minnehaha County | 99 | Sioux Falls | 1862 | 169,468 | 809 | 2,095 |
| Moody County | 101 | Flandreau | 1873 | 6,486 | 520 | 1,347 |
| Oglala Lakota County | 102 | | 1875 | 13,586 | 2,094 | 5,423 |
| Pennington County | 103 | Rapid City | 1875 | 100,948 | 2,776 | 7,190 |
| Perkins County | 105 | Bison | 1909 | 2,982 | 2,872 | 7,438 |
| Potter County | 107 | Gettysburg | 1875 | 2,329 | 866 | 2,243 |
| Roberts County | 109 | Sisseton | 1883 | 10,149 | 1,101 | 2,852 |
| Sanborn County | 111 | Woonsocket | 1883 | 2,355 | 569 | 1,474 |
| Spink County | 115 | Redfield | 1873 | 6,451 | 1,504 | 3,895 |
| Stanley County | 117 | Fort Pierre | 1873 | 2,966 | 1,443 | 3,737 |
| Sully County | 119 | Onida | 1873 | 1,373 | 1,007 | 2,608 |
| Todd County | 121 | | 1909 | 9,612 | 1,388 | 3,595 |
| Tripp County | 123 | Winner | 1873 | 5,644 | 1,614 | 4,180 |
| Turner County | 125 | Parker | 1871 | 8,347 | 617 | 1,598 |
| Union County | 127 | Elk Point | 1862 | 14,399 | 460 | 1,191 |
| Walworth County | 129 | Selby | 1873 | 5,438 | 708 | 1,834 |
| Yankton County | 135 | Yankton | 1862 | 22,438 | 522 | 1,352 |
| Ziebach County | 137 | Dupree | 1911 | 2,801 | 1,962 | 5,082 |
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