Doncaster is a city in South Yorkshire, England. Named after the River Don, it is the administrative centre of the larger City of Doncaster, and is the second largest settlement in South Yorkshire after Sheffield. Noted for its horse racing and railway history, it is situated in the Don Valley on the western edge of the Humberhead Levels and east of the Pennines. The urban subdivision had a population of 113,566 at the 2021 census, whilst the City of Doncaster metropolitan borough had a population of 308,106.