Windsor is a historic town in the Royal Borough of Windsor and Maidenhead in Berkshire, England. It is the site of Windsor Castle, one of the official residences of the British monarch. The town is situated 21.8 miles (35.1 km) west of Charing Cross, central London, 5.8 miles (9.3 km) southeast of Maidenhead, and 15.8 miles (25.4 km) east of the modern county town of Reading. It is immediately south of the River Thames, which forms its boundary with its smaller, ancient twin town of Eton. The village of Old Windsor, just over 2 miles (3 km) to the south, predates what is now called Windsor by around 300 years. In the past, Windsor was formally referred to as New Windsor to distinguish the two.

Eton is a town in Berkshire, England, on the opposite bank of the River Thames to Windsor, connected to it by Windsor Bridge. The civil parish, which also includes the village of Eton Wick two miles west of the town, had a population of 4,692 at the 2011 Census. Within the boundaries of the historic county of Buckinghamshire, in 1974 it came under the administration of Berkshire following the Local Government Act 1972; since 1998 it has been part of the unitary authority of Windsor and Maidenhead. The town is best known as the location of Eton College.