Thomas Townshend, 1st Viscount Sydney was a British politician who sat in the House of Commons from 1754 to 1783 when he was raised to the peerage as Baron Sydney. He held several important Cabinet posts in the second half of the 18th century. The cities of Sydney in Nova Scotia, Canada, and Sydney in New South Wales, Australia were named in his honour, in 1785 and 1788, respectively.

Sydney is a former city and urban community on the east coast of Cape Breton Island in Nova Scotia, Canada within the Cape Breton Regional Municipality. Sydney was founded in 1785 by the British, was incorporated as a city in 1904, and dissolved on 1 August 1995, when it was amalgamated into the regional municipality.