| State: | SD |
| Type: | SD |
| Route: | 239 |
| Section: | 215 |
| Map Custom: | yes |
| Map Notes: | SD 239 highlighted in red |
| Length Mi: | 7.312 |
| Length Ref: | [1] |
| Direction A: | South |
| Terminus A: | near Eureka |
| Direction B: | North |
| Terminus B: | 106th Street in Long Lake |
| Counties: | McPherson |
| Previous Type: | SD |
| Previous Route: | 235 |
| Next Type: | SD |
| Next Route: | 240 |
South Dakota Highway 239 (SD 239) is a 7.312adj=midNaNadj=mid state highway located entirely within McPherson County, South Dakota. Its southern terminus is at an intersection with SD 10/SD 45. This terminus is located about 12miles west-northwest of Leola and about 19.7miles east-southeast of Eureka. Its northern terminus is at 106th Street in the small community of Long Lake.
SD 239 begins at an intersection with SD 10 / SD 45 south of Long Lake. Here, the roadway continues to the south as 350th Avenue. It travels to the north. Approximately 3miles4miles later, SD 239 curves slightly east to bypass a small lake. It then curves back to the west and straightens out to a due north course for the last 3miles before it terminates at 106th Stree on the south side of Long Lake. SD 239 then becomes 350th Avenue after this terminus, which continues to the North Dakota state line.