Sumner Township is one of sixteen townships in Buchanan County, Iowa, USA.

As of the 2000 census, its population was 3,148.

Sumner Township covers an area of 34.31 square miles (88.9 km2) and contains the southern half of the city of Independence.

According to the USGS, it contains four cemeteries: Mount Hope, Oakwood, State Hospital and Wilson.

This article about the geography of Buchanan County, Iowa is a stub.