Northumberland County (2006 population 80,963) is situated on the north shore of Lake Ontario, in east-central Ontario, Canada. Located east of Durham County (now the Regional Municipality of Durham), west of Hastings, southeast of Kawartha Lakes and south of Peterborough County. The county seat is Cobourg. Together with Durham County, it formed the Newcastle District from 1798 to 1849 and the United Counties of Northumberland and Durham from 1850 to 1973.
It was first aggressively settled by United Empire Loyalists fleeing the former 13 British American Colonies in the late 18th century. The Crown provided plots to the settlers for nominal sums (with the stipulation of making the land productive in a set number of years) or gratis to those who had served against the American Colonial Army. Following the war of 1812 many port towns, Cobourg in particular became important centres for commercial activity and a landing point for European immigrants arriving on steamers.
It consists of: