Walnut Grove Township is one of twenty-one townships in Knox County, Illinois, USA.

As of the 2010 census, its population was 770 and it contained 329 housing units.

[2] According to the 2010 census, the township has a total area of 35.63 square miles (92.3 km2), of which 35.51 square miles (92.0 km2) (or 99.66%) is land and 0.12 square miles (0.31 km2) (or 0.34%) is water.

[2] The township contains these three cemeteries: Altona, Larson and Walnut Grove.