Rex township
- County:
- Lyman County
- County Seat:
- No
- Area (mi²):
- 35.829
- State:
- South Dakota
Rex township is located in Lyman County, South Dakota. Rex township has a 2026 population of 23. Rex township is currently declining at a rate of 0% annually and its population has decreased by 0% since the most recent census, which recorded a population of 23 in 2020.