Sydney, city (1991 pop. 26,063), Cape Breton Island, N.S., Canada, on the northeast coast at the head of the South Arm of Sydney Harbour. It is the port and the commercial, trade, and industrial center in a former coal-mining area. The city has steel mills and plants manufacturing wood, aluminum, food products, and chemicals. Sydney was founded (1783) by United Empire Loyalists and was the capital (1784–1820) of Cape Breton prov. St. George's Church (1786) is one of the oldest Anglican churches in Canada.