South Grove Township is one of nineteen townships in DeKalb County, Illinois, USA. As of the 2010 census, its population was 512 and it contained 209 housing units. South Grove Township was renamed from Vernon Township on November 20, 1850.
Past and Present of DeKalb County, Illinois - Volume I published in 1907 covers the early history of DeKalb County, including this township. On Page 127 it reads: "South Grove was named Driscoll's Grove before the township organization of the county in 1850. It was then called Vernon, and finally South Grove, as it was the first grove south of the large woods along the Kishwaukee in the north part of the county.