Milton Keynestown and unitary authority, geographic and historic county of Buckinghamshire, south-central England. There is no single urban centre within the borough, but the whole area, which contains several preexisting towns, has been developed as a new town since 1967. The southern part of the unitary authority is mainly urban, while the north remains largely rural.

The unitary authority area has attracted people, offices, and industry to become an area of striking growth. Earlier, the towns of Bletchley, Wolverton, and Newport Pagnell all had built-up industries, the first two largely because of their position on, and connection with, the main railway from London to the Midlands and the north. The location of the modern unitary authority has increased its attractiveness to commerce and industry. From Bletchley there is an excellent rail service to London, and the M1 motorway bisects the district. Many firms have established bases in the area. Among the most important cultural institutions in Milton Keynes is the Open University, whose students receive instruction by correspondence and through the media. Area, unitary authority, 120 square miles (310 square km). Pop. (2005 est.) 2001) urban area, 184,506; unitary authority, 218,500207,057; (2011) unitary authority, 248,821.