Hainesville is a village in Avon Township, Lake County, Illinois, United States. As of the 2010 census, it had a population of 3,597. 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 City 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.