Union Township is one of twenty townships in Fayette County, Iowa, USA. As of the 2010 census, its population was 412.It was previously called West Union township.GeographyAccording to the United States Census Bureau, Union Township covers an area of 33.67 square miles (87.2 square kilometers).The city of West Union is entirely within this township geographically but is a separate entity.Adjacent townshipsDover Township (north)Clermont Township (northeast)Pleasant Valley Township (east)Illyria Township (southeast)Westfield Township (south)Center Township (southwest)Windsor Township (west)Auburn Township (northwest)CemeteriesThe township contains these five cemeteries: Barnhouse, Butler, Mount Calvary, Mount Pleasant and Pleasant Grove.