Mill Hill is a suburb in the London Borough of Barnet, England. It is situated around 9 miles northwest of Charing Cross, close to the Hertfordshire border. It was in the historic county of Middlesex until 1965, when it became part of Greater London. Its population was 18,451 in 2011. It consists of the original Mill Hill Village; the later-developed Mill Hill Broadway; and Mill Hill East, alongside large swathes of countryside.