Knowlton is an unincorporated community in Ringgold County, Iowa, United States.

[1] Knowlton is located at the intersection of county highways J23 and P33, 1.3 miles (2.1 km) north of Diagonal.

An article appeared in the newspaper on August 25, 1895 announcing that it was likely arson committed by a resident of Diagonal, as the towns had a rivalry.

[3] The population of Knowlton declined after a new rail line came through Diagonal, and many people moved to the rival town.

Eventually when the Great Western Railroad withdrew its support, Knowlton became a ghost town.