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 to 62,000 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.
The area was called Walkers' Grove until it was platted as Plainfield in 1841. It was originally settled by a large community of Potawatomi, and the land was later bequeathed to the United States as part of the Treaty of St. Louis (1816) with the Council of the Three Fires. Indian Boundary Road aligns with the western border of the tract of land originally ceded.
The earliest Europeans in the area were French fur traders. The first European settler in the area was James Walker, who traveled with his father-in-law, Methodist Reverend Jessie Walker traveled here in 1826 where he established a small mission for the Potawatomi Indians. James Walker, Jesse Walker's son-in-law, traveled with him and became the first European to claim land in the area in 1828.
In 1828, James Walker, in the company of several men, erected a sawmill around which the settlement of Walkers' Grove developed.
Plainfield is identified as the oldest community in Will County because the earliest settlement of Walkers' Grove was established on the banks of the DuPage River by 1828. However, the actual Village of Plainfield was platted immediately north of Walkers' Grove in 1834 by Chester Ingersoll. The separate community of East Plainfield was platted in June 1836 by James Mathers who began selling lots in July 1836. In addition he also constructed a gristmill and a mill race west of Water Street. Water Street would later become Plainfield-Naperville Road. Ingersoll's Planefield (Plainfield)which comprised lots in Section 16, along with Mather's East Plainfield lots in Section 10 and Levi Arnold's plat of Section 9 all became joined to create the present-day village after the death of Levi Arnolds in 1845.
Walkers' Grove flourished because of the DuPage River and established routes to Fort Dearborn in Chicago, as well as to Ottawa. Reuben Flagg hauled lumber from Walker's mill to Chicago in order to erect the first two frame structures in the city (P.F.W. Peck House and the George Dole Forwarding House). Chicago also depended upon the settlement for mail and supplies. This led to Plainfield being known as "The Mother of Chicago."
The community's early prosperity was stunted when the Illinois & Michigan Canal opened in 1848, because the Village was not located along the canal. Located within the Village are numerous Greek Revival, upright-and-wing cottages, a school built in 1847 (which may be the ), and a number of early-19th-century homes. Plainfield currently has three buildings listed on the National Register of Historic Places: Plainfield House, Flanders House and a 1928 Standard Oil Gas Station.
At one time, the two longest paved highways in the world (Lincoln Highway and U.S. Route 66) crossed within Plainfield. The highways only crossed each other twice and both locations are in Will County. The other location is in neighboring Joliet.
Plainfield is also the birthplace of Eddie Gardner, one of the pilots credited with establishing the transcontinental air mail routes for the United States Postal Service. The earliest architects associated with buildings in Plainfield are J.E. Minott of Aurora; G. Julian & John Barnes of Joliet; and Herbert Cowell of Joliet and Plainfield.
North Central College was first founded in the village in 1861 as Plainfield College.
Plainfield Public Library District was first founded in the village in 1925 as the Nimmons Village of Plainfield Free Public Library.
A population explosion started to take form at the start of the 21st century caused by the sale of many farms. This made way for a large number of new home subdivisions. Before the population boom, Plainfield was primarily an agricultural town.
Certain older parts of Plainfield have suffered from extreme traffic congestion. Before Interstate 55 was built just east of the town in the late 1950s, U.S. Route 30, The Lincoln Highway and U.S. Route 66 (sometimes referred to as "The Mother Road") merged into one street for three blocks on what is now Illinois Route 59. This merge is now only shared by U.S. 30 and Lincoln Highway, between Plainfield/Joliet Road on the south to Lockport Street on the north, but continues to be an area of heavy traffic congestion even outside heavy commuting periods.