Middlefield Township is one of sixteen townships in Buchanan County, Iowa, United States.

As of the 2000 census, its population was 304.

Middlefield Township was established in 1858.

[3] Middlefield Township covers an area of 34.97 square miles (90.6 km2) and contains no incorporated settlements.

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