Historically Monken Hadley was a civil parish of Middlesex forming part of a small protrusion into Hertfordshire. In 1889, under the Local Government Act 1888, the civil parish was transferred to Hertfordshire. Under the Local Government Act 1894 the parish was split with a Hadley parish becoming part of the Barnet Urban District, while the remaining part of the parish became part of the East Barnet Urban District of Hertfordshire. In 1965, under the London Government Act 1963, its area was transferred to Greater London and combined with that of other districts formerly in Hertfordshire and Middlesex to form the present-day London Borough of Barnet.