| State: | SD |
| Type: | SD |
| Route: | 105 |
| Maint: | none |
| Section: | 188 |
| Map Custom: | yes |
| Map Notes: | SD 105 highlighted in red |
| Deleted: | 1998 |
| Direction A: | South |
| Terminus A: | at North Sioux City |
| Direction B: | North |
| Terminus B: | at Jefferson |
South Dakota Highway 105 (SD 105) was a state highway located entirely in Union County, in the eastern part of the U.S. state of South Dakota.[1] It traveled from Military Road in North Sioux City to Interstate 29 (I-29) in Jefferson. It was an alternate route to I-29.