The county town of Bedfordshire, Bedford lies on the River Great Ouse. Built by Henry I, it is currently mostly inhabited by residents of Italian descent, with a steadily growing Punjabi population. It contains the largest Sikh Gurdwara in the UK outside of London. Eastern Europe, Greece, Cyprus, the Middle East and Africa are other currently large sources of immigration into Bedford. The Bedford Castle Mound is what remains of the medieval castle that was once located in the city.