Hainesville is a village in Avon Township, Lake County, Illinois, United States.

[2] 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.

During the winter of 1841–42, Haines taught school in Waukegan, Illinois (then known as Little Fort).

By 1851, the road was completed to Squaw Creek just west of Hainesville, and the settlement became the location for one of three toll houses.

In 1899, the Milwaukee Road railroad expanded into Lake County, providing convenient transportation from the area into Chicago.

Local land owner, general store proprietor and Hainesville postmaster George Battershall asked for a large sum of money to build a train station in Hainesville.

Amarias M. White, an early settler of what is now Round Lake, knowing that a railroad stop in Round Lake would spark commerce for his area, attracted the railroad company by offering the land for a depot for free.

After several decades of being not much more than a handful of crossroads, Hainesville finally exploded into a sprawling suburban neighborhood.

In 2001, the former Softball City, a multi-use sports complex adjacent to the Avon Township Youth Baseball Organization facilities, sold its land to Ryland Homes, and this became the townhouse community called Union Square.

Due to the explosive growth within Lake County, a special census was requested in 2004 yielding a population totaling 3,444.

Pace provides bus service on Route 570 connecting Hainesville to Fox Lake, Grayslake and other destinations.