Chatham (2001 urban population 43,690, municipality population 107,341) is a city located in southwestern Ontario, Canada.

In 1998 the Chatham city government merged with that of Kent County to form the city of Chatham-Kent. The "municipality population" listed above is that of the new city of Chatham-Kent, while the "urban population" is for the area within the old boundaries of the City of Chatham.