Union Township is one of twelve townships in Floyd County, Iowa, United States.

As of the 2000 census, its population was 682.

[1] According to the United States Census Bureau, Union Township covers an area of 41.16 square miles (106.59 square kilometers); of this, 40.78 square miles (105.63 square kilometers, 99.1 percent) is land and 0.37 square miles (0.97 square kilometers, 0.91 percent) is water.

(This list is based on USGS data and may include former settlements.)

The township contains these three cemeteries: Hillside, Westside and St. Mary's Catholic, Roseville, Iowa.