| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| La Plant | city | South Dakota | United States | 45.14 | -100.65 | 1955 | |
| LaBolt | city | South Dakota | United States | 45.05 | -96.68 | 1669 | |
| LaCreek (historical) | city | South Dakota | United States | 43.09 | -101.65 | 3349 | |
| LaDelle | city | South Dakota | United States | 44.68 | -98.12 | 1669 | |
| Lacy | city | South Dakota | United States | 44.50 | -100.70 | 2001 | |
| Ladner | city | South Dakota | United States | 45.83 | -103.73 | 3349 | |
| Lake Andes | city | South Dakota | United States | 43.16 | -98.54 | 1669 | |
| Lake City | city | South Dakota | United States | 45.73 | -97.41 | 1850 | |
| Lake Norden | city | South Dakota | United States | 44.58 | -97.21 | 1669 | |
| Lake Preston | city | South Dakota | United States | 44.36 | -97.38 | 1719 | |
| Lake View Colony | city | South Dakota | United States | 43.22 | -98.46 | 1669 | |
| Lakeport | city | South Dakota | United States | 42.91 | -97.58 | 1669 | |
| Lakeview | city | South Dakota | United States | 43.10 | -100.75 | 2900 | |
| Lakota Homes | city | South Dakota | United States | 44.11 | -103.22 | 3359 | |
| Lancaster City (historical) | city | South Dakota | United States | 44.38 | -103.77 | 5045 | |
| Lane | city | South Dakota | United States | 44.07 | -98.43 | 1669 | |
| Langford | city | South Dakota | United States | 45.60 | -97.83 | 1669 | |
| Lantry | city | South Dakota | United States | 45.01 | -101.43 | 2509 | |
| Lead | city | South Dakota | United States | 44.35 | -103.77 | 5154 | |
| Lebanon | city | South Dakota | United States | 45.07 | -99.77 | 1968 | |
| Lees Corner | city | South Dakota | United States | 44.08 | -99.33 | 1669 | |
| Lemmon | city | South Dakota | United States | 45.94 | -102.16 | 2598 | |
| Lennox | city | South Dakota | United States | 43.35 | -96.89 | 1669 | |
| Leola | city | South Dakota | United States | 45.72 | -98.94 | 1669 | |
| Lesterville | city | South Dakota | United States | 43.04 | -97.60 | 1669 | |
| Letcher | city | South Dakota | United States | 43.90 | -98.14 | 1669 | |
| Lily | city | South Dakota | United States | 45.18 | -97.68 | 1843 | |
| Lily (historical) | city | South Dakota | United States | 45.07 | -97.74 | 1751 | |
| Linden Beach | city | South Dakota | United States | 45.40 | -96.65 | 1007 | |
| Little Eagle | city | South Dakota | United States | 45.68 | -100.80 | 1669 | |
| Littleburg | city | South Dakota | United States | 43.05 | -100.45 | 2700 | |
| Lodgepole | city | South Dakota | United States | 45.80 | -102.66 | 2798 | |
| Lodi | city | South Dakota | United States | 42.98 | -96.98 | 1220 | |
| Lone Tree | city | South Dakota | United States | 43.98 | -96.73 | 1669 | |
| Long Hollow Housing | city | South Dakota | United States | 45.69 | -97.15 | 1669 | |
| Long Lake | city | South Dakota | United States | 45.86 | -99.21 | 1955 | |
| Long Lake Colony | city | South Dakota | United States | 45.61 | -98.82 | 1669 | |
| Long Valley | city | South Dakota | United States | 43.46 | -101.49 | 2700 | |
| Loomis | city | South Dakota | United States | 43.79 | -98.10 | 1669 | |
| Lower Brule | city | South Dakota | United States | 44.08 | -99.58 | 1669 | |
| Lowry | city | South Dakota | United States | 45.32 | -99.98 | 1981 | |
| Loyalton | city | South Dakota | United States | 45.29 | -99.28 | 1669 | |
| Lucas | city | South Dakota | United States | 43.29 | -99.22 | 2057 | |
| Lucerne | city | South Dakota | United States | 44.24 | -101.53 | 2509 | |
| Ludlow | city | South Dakota | United States | 45.83 | -103.38 | 3349 | |
| Lyman | city | South Dakota | United States | 43.88 | -99.74 | 1788 | |
| Lyons | city | South Dakota | United States | 43.72 | -96.87 | 1669 | |
| Lyonville | city | South Dakota | United States | 43.88 | -98.97 | 1669 |