Washington Township is a township in Jasper County, Iowa, United States.[1] History Washington Township was established in 1861.[2] References [1]U.S. Geological Survey Geographic Names Information System: Washington Township, Jasper County, Iowa [2]Weaver, James Baird (1912). Past and Present of Jasper County, Iowa, Volume 1. B.F. Bowen. p. 53. 41.6472°N 93.2986°W / 41.6472; -93.2986 This article about the geography of Jasper County, Iowa is a stub. You can help Wikipedia by expanding it.vteWikiwand - on Seamless Wikipedia browsing. On steroids.