Union Township is a township in Dallas County, Iowa, USA.

Union Township covers an area of 39.83 square miles (103.2 km2) and contains two incorporated settlements: Dexter and Redfield.

According to the USGS, it contains five cemeteries: Bear Creek, Dexter, Pleasant Hill, Spillers and Wiscotta.

The stream of Middle Raccoon River runs through this township.

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