| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
| La Plant | city | South Dakota | United States | 45.14472 | -100.65111 | 1955 | 98 |
| LaBolt | city | South Dakota | United States | 45.05083 | -96.67639 | 1299 | 187 |
| LaDelle | city | South Dakota | United States | 44.67528 | -98.11861 | 1332 | 168 |
| Lacy | city | South Dakota | United States | 44.49556 | -100.70083 | 2001 | 75 |
| Ladner | city | South Dakota | United States | 45.82722 | -103.7275 | 3097 | 19 |
| Lake Andes | city | South Dakota | United States | 43.15639 | -98.54111 | 1453 | 369 |
| Lake City | city | South Dakota | United States | 45.72528 | -97.41417 | 1850 | 192 |
| Lake Norden | city | South Dakota | United States | 44.58056 | -97.20889 | 1669 | 339 |
| Lake Preston | city | South Dakota | United States | 44.36361 | -97.37694 | 1719 | 308 |
| Lakeport | city | South Dakota | United States | 42.90833 | -97.57917 | 1587 | 1857 |
| Lakeview | city | South Dakota | United States | 43.10361 | -100.74778 | 2900 | 255 |
| Lakota Homes | city | South Dakota | United States | 44.10833 | -103.21806 | 3359 | 38939 |
| Lancaster City historical | city | South Dakota | United States | 44.37917 | -103.77361 | 5059 | 1831 |
| Lane | city | South Dakota | United States | 44.06972 | -98.42472 | 1374 | 103 |
| Langford | city | South Dakota | United States | 45.6025 | -97.83 | 1377 | 201 |
| Lantry | city | South Dakota | United States | 45.01444 | -101.43111 | 2404 | 85 |
| Lead | city | South Dakota | United States | 44.35222 | -103.76472 | 5154 | 1991 |
| Lebanon | city | South Dakota | United States | 45.06972 | -99.76944 | 1968 | 140 |
| Lees Corner | city | South Dakota | United States | 44.0775 | -99.325 | 1663 | 159 |
| Lemmon | city | South Dakota | United States | 45.94083 | -102.15889 | 2598 | 56 |
| Lennox | city | South Dakota | United States | 43.35417 | -96.89167 | 1325 | 1318 |
| Leola | city | South Dakota | United States | 45.72278 | -98.94056 | 1587 | 112 |
| Lesterville | city | South Dakota | United States | 43.03944 | -97.59528 | 1384 | 455 |
| Letcher | city | South Dakota | United States | 43.89722 | -98.13833 | 1312 | 194 |
| Lily | city | South Dakota | United States | 45.18139 | -97.68306 | 1843 | 159 |
| Lily historical | city | South Dakota | United States | 45.07083 | -97.7375 | 1797 | 238 |
| Linden Beach | city | South Dakota | United States | 45.40472 | -96.64833 | 1007 | 345 |
| Little Eagle | city | South Dakota | United States | 45.67583 | -100.80389 | 1633 | 70 |
| Littleburg | city | South Dakota | United States | 43.045 | -100.45167 | 2700 | 201 |
| Lodgepole | city | South Dakota | United States | 45.80472 | -102.66028 | 2798 | 56 |
| Lodi | city | South Dakota | United States | 42.9825 | -96.98361 | 1220 | 336 |
| Lone Tree | city | South Dakota | United States | 43.97889 | -96.72889 | 1650 | 608 |
| Long Hollow Housing | city | South Dakota | United States | 45.68722 | -97.15306 | 1558 | 481 |
| Long Lake | city | South Dakota | United States | 45.85667 | -99.20472 | 1955 | 103 |
| Long Lake Colony | city | South Dakota | United States | 45.60667 | -98.81917 | 1476 | 134 |
| Long Valley | city | South Dakota | United States | 43.46167 | -101.49444 | 2700 | 61 |
| Loomis | city | South Dakota | United States | 43.79389 | -98.10417 | 1286 | 886 |
| Lower Brule | city | South Dakota | United States | 44.07889 | -99.58111 | 1443 | 106 |
| Lowry | city | South Dakota | United States | 45.31611 | -99.98222 | 1981 | 112 |
| Loyalton | city | South Dakota | United States | 45.28639 | -99.27917 | 1676 | 132 |
| Lucas | city | South Dakota | United States | 43.28972 | -99.21611 | 2057 | 244 |
| Lucerne | city | South Dakota | United States | 44.23917 | -101.52583 | 2401 | 56 |
| Ludlow | city | South Dakota | United States | 45.83444 | -103.37611 | 3083 | 19 |
| Lyman | city | South Dakota | United States | 43.88111 | -99.73917 | 1788 | 98 |
| Lyons | city | South Dakota | United States | 43.72306 | -96.8675 | 1574 | 655 |
| Lyonville | city | South Dakota | United States | 43.87778 | -98.97028 | 1650 | 147 |
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