Plainfield is a village in Will County, Illinois, United States. The US Census Bureau estimates the population at 41,734 as of 2013.The village includes land in Plainfield and Wheatland townships. Part of Plainfield is located in Kendall County. With the growth in the Chicago suburbs in the 1990s and 2000s, the village has seen a population increase, from 4,500 in 1990 to 28,000 in 2000 to more than 37,000 in 2007.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.