Plainfield is a village in Will County, Illinois, United States. As of the 2007 special census, the population is 37,334.
The Village includes land in Plainfield and Wheatland townships. Part of Plainfield is located in Kendall County (Na-Au-Say and Oswego townships). With the growth in the Chicago suburbs in the 1990s and 2000s, the village has seen a building boom and a rapid population increase, from 4,500 in 1990 to 13,000 in 2000 to over 37,000 in 2007. Based on estimates created by the village and state government, Plainfield's population could grow as large as 120,000 by 2030. Plainfield is also the fastest growing village in Will county.
The Village has established a community Preservation Commission and historic preservation ordinance. It is the home of the Lake Renwick Preserve, a county forest preserve used for birdwatching and other activities.