 Ellsworth Township was organized in 1868, and named for Colonel Elmer E. Ellsworth, friend of Abraham Lincoln often called the "first conspicuous casualty" of the American Civil War.According to the United States Census Bureau, the township has a total area of , of which of it is land and of it (18.89%) is water.Ellsworth Township is located in Township 118 North of the Arkansas Base Line and Range 30 West of the 5th Principal Meridian.