Truro is a cathedral city and civil parish in Cornwall, England. It is Cornwall's county town, sole city and centre for administration, leisure and retail trading. Its population was 18,766 in the 2011 census. People of Truro can be called Truronians. It grew as a trade centre through its port and as a stannary town for tin mining. It became mainland Britain's southernmost city in 1876, with the founding of the Diocese of Truro. Sights include the Royal Cornwall Museum, Truro Cathedral, the Hall for Cornwall and Cornwall's Courts of Justice.