Parker's Piece is a 25-acre (100,000 m2) flat and roughly square green common located near the centre of Cambridge, England, regarded by some as the birthplace of the rules of association football. The two main walking and cycling paths across it run diagonally, and the single lamp-post at the junction is colloquially known as Reality Checkpoint. The area is bounded by Park Terrace, Parkside, Gonville Place, and Regent Terrace. The Cambridge University Football Club Laws were first used on Parker's Piece and adopted by the Football Association in 1863. "They embrace the true principles of the game, with the greatest simplicity". 'The Cambridge Rules appear to be the most desirable for the Association to adopt'.

Cambridge is a city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, 55 miles (89 km) north of London. As of the 2021 United Kingdom census, the population of the City of Cambridge was 145,700; the population of the wider built-up area was 181,137. Cambridge became an important trading centre during the Roman and Viking ages, and there is archaeological evidence of settlement in the area as early as the Bronze Age. The first town charters were granted in the 12th century, although modern city status was not officially conferred until 1951.