Hainesville is a village in the Avon Township of Lake County, Illinois, United States. Hainesville has the distinction of being the oldest incorporated community within Lake County.
In 1838 a young boy named Elijah M. Haines (1822–1889) and his family moved from New York to the Chicago area. In 1836, the young boy purchased a farm in Hainesville. During the winter of 1841–42, Haines taught school in Waukegan, Illinois (then known as Little Fort). In 1846, he surveyed and platted Hainesville. On February 26, 1847, the village incorporation papers were drafted. It is recorded that Elijah Haines met Abraham Lincoln in 1847. The two men met frequently and became well acquainted. It has been said[by whom?] that Lincoln spent the night in Hainesville a few times.
In 1848, construction began on the Lake and McHenry Plank Road. By 1851, the road was completed to Squaw Creek just west of Hainesville and Haineville became the location for one of three toll houses.