Plainfield is a town in Guilford, Liberty, and Washington townships, Hendricks County, Indiana, United States. The population was 27,631 at the 2010 census, and in 2019 the estimated population was 35,287.In 1822 a tract of land which included the area now known as Plainfield was obtained by Jeremiah Hadley of Preble County, Ohio. Ten years later he sold it to his son, Elias Hadley. Levi Jessup and Elias Hadley laid out the town in 1839. Plainfield was incorporated as a town in 1839. The town got its name from the early Friends (Quakers) who settled around the area and established several meetinghouses throughout the county, including the important Western Yearly Meeting of Friends in Plainfield. The Friends were “plain” people, and thus the name “Plainfield”.
The high school continues to honor the Quakers, using the name for the school’s mascot. Plainfield has long been associated with the National Road, U.S. Route 40, which goes through town as Main Street. One incident which brought Plainfield national attention occurred in 1842 when former President Martin Van Buren was spilled deliberately from his stagecoach into the thick mud of the highway. The practical joke came as a result of Van Buren’s vetoing a bill from Congress to improve the highway, a move which angered Western settlers. When Van Buren came through Plainfield on a swing to shore up his popularity for the 1844 election, a group of perpetrators set up the incident.
information provided by wikipedia.org