Oregon Township, Washington County, Iowa

Ainsworth is a city in Washington County, Iowa, United States. It is a part of the Iowa City, Iowa Metropolitan Statistical Area. The population was 511 at the 2020 census. It is part of the Highland Community School District.

Haskins is an unincorporated community in Washington County, Iowa, United States.

County Line Bridge is a historic structure located in a rural area west of Columbus Junction, Iowa, United States. The Louisa County Board of Supervisors approved the petition of Thomas Anwyl in April 1893 to build a bridge over Long Creek on the Louisa-Washington county line. They awarded a $1,174 contract to the Gillette-Herzog Manufacturing Company of Minneapolis to build two bridges. The second span was the Gipple's Quarry Bridge over Buffington Creek in Elm Grove Township. The bridge span is supported by cast iron columns that were manufactured by the Cast Iron Pile and Bridge Company of Keosauqua, Iowa. The steel components were rolled by Carnegie for Gillette-Herzog in Pittsburgh. The pony truss bridge is typical of those built in the same era in Iowa, however, like Gipple's Quarry Bridge it has an unusual lower chord configuration with end panels that slope downward from the bearing shoes to the center panels. It has subsequently been abandoned. The bridge was listed on the National Register of Historic Places in 1998.

Cotter is a city in western Louisa County, Iowa, United States. The population was 39 at the 2020 census. It is part of the Muscatine Micropolitan Statistical Area.

Crawfordsville is a city in Washington County, Iowa, United States. It is part of the Iowa City, Iowa Metropolitan Statistical Area. The population was 277 at the 2020 census.

Crawford Township is a township in Washington County, Iowa, United States.

Highland Township is a township in Washington County, Iowa, United States.

Goose Creek is a stream in Louisa and Washington counties, Iowa, in the United States. It is a tributary of the Iowa River. Goose Creek was the home to a large flock of wild geese, hence the name.

Noble is an unincorporated community in Washington County, Iowa, United States.

Columbus City Township is a township in Louisa County, Iowa. It was organized in 1841.

Marion Township is a township in Washington County, Iowa, United States.

Olds is a city in Henry County, Iowa, United States. The population was 192 at the time of the 2020 census.