Millersburg Township is located in Mercer County, Illinois.

[2] Millersburg is named after George Abraham Miller, a Primitive Baptist who, with several families, settled in Mercer County, Illinois on the Edwards River in 1834.

These families traveled from Crawfordsville, Montgomery County, Indiana for the purpose of expanding the church into the area.

[3] The Church was disbanded in 1847, and the last of the Original settlers Isaac Miller, left for Oregon in 1851.

According to the 2010 census, the township has a total area of 36.32 square miles (94.1 km2), all land.