Flat Branch township
- County:
- Shelby County
- County Seat:
- No
- Area (mi²):
- 33.773
- State:
- Illinois
Flat Branch township is located in Shelby County, Illinois. Flat Branch township has a 2026 population of 413. Flat Branch township is currently growing at a rate of 0.24% annually but its population has decreased by -1.43% since the most recent census, which recorded a population of 419 in 2020.
The median household income in Flat Branch township is $108,056 with a poverty rate of 2.86%. The median age in Flat Branch township is 55.6 years: 51.9 years for males, and 55.8 years for females. For every 100 females there are 131.6 males.