Goswell Road, in Central London, is an end part of the A1. The southern part ends with one block, on the east side, in City of London; the rest is in the London Borough of Islington, the north end being Angel. It crosses Old Street/Clerkenwell Road. In the north it splits Clerkenwell from Finsbury; the south was sometimes used as a demarcator but all but the southern corporate/legal/financial end in the modern era forms the heart of the highly developed mixed-use district Barbican.

The A1 in London is the southern part of the A1 road. It starts at Aldersgate in the City of London, passing through the capital to Borehamwood on the northern fringe of Greater London, before continuing to Edinburgh. The road travels through the City and three London boroughs: Islington, Haringey and Barnet, which include the districts of Islington, Holloway, Highgate, Hendon and Mill Hill, and travels along Upper Street and Holloway Road, crossing the North Circular Road in Hendon, a district in the London Borough of Barnet.