Parts of this article (those related to demographics) need to be updated. Please help update this article to reflect recent events or newly available information.(January 2024)
According to the United States Census Bureau, Rock Grove Township covers an area of 39.92 square miles (103.4 km2) of which 39.89 square miles (103.3 km2) {99.93 percent) is land and 0.03 square miles (0.078 km2) (0.07 percent) is water.