In England, the name Chatham came from the British root ceto and the Old English ham thus meaning a forest settlement.Following the American Revolution and the Gnadenhutten Massacre, a group of Christian Munsee Indians settled in what is now Moraviantown.
A steamboat offered transportation to Windsor and Detroit. Before 1998, Kent County consisted of the townships of Camden, Chatham, Dover, Harwich, Howard, Orford, Raleigh, Romney, Tilbury East and Zone.
In some of Canada's earliest post-Confederation censuses, some residences in Kent County were incorrectly reported as being in Bothwell "County", which was a separate electoral district comprising parts of Kent and Lambton counties but not a distinct county in its own right.
In 1998 the County of Kent and the city of Chatham were amalgamated to form the Municipality of Chatham–Kent. Since then, bus service has begun to serve all of Chatham-Kent.
Starting in 2007, routes were set up to include the former towns of Wallaceburg and Dresden.
The municipality's census division, inclusive of the separate Delaware Nation at Moraviantown First Nation, had a population of 102,042 in the 2016 census.