Spring Bay Township is located in Woodford County, Illinois, United States. As of the 2010 census, its population was 2,643 and it contained 1,133 housing units.

Geography

According to the 2010 census, the township has a total area of 16.92 square miles (43.8 km), of which 10.28 square miles (26.6 km) (or 60.76%) is land and 6.64 square miles (17.2 km) (or 39.24%) is water.

Demographics

Historical population

Census	Pop.	Note	%±
2016 (est.)	2,685
U.S. Decennial Census