Template:Infobox UK place South Mimms, sometimes spelt South Mymms, is a village and civil parish forming part of the Hertsmere district of Hertfordshire in the East of England.
It is a small settlement located near to the junction of the M25 motorway with the A1(M) motorway and is perhaps more widely known because of the naming of the service station at that junction.
Potters Bar was originally a small settlement in the parish of South Mimms. Potters Bar became the location of the nearest railway station and eventually became much larger. Both Potters Bar and South Mimms were part of Middlesex until the creation of Greater London, which abolished the county of Middlesex in 1965. South Mimms was the northernmost village in Middlesex.
South Mimms parish was split in 1894 under the Local Government Act 1894 with the extreme southern tip forming South Mimms Urban parish in the Barnet Urban District and was transferred to Hertfordshire. This area now forms part of the London Borough of Barnet. The rest of the parish became the South Mimms Rural District, later renamed the Potters Bar Urban District.
South Mimms served as a home for Queen Wilhelmina of the Netherlands during her exile in World War II. A German air attack on South Mimms at this time narrowly missed her, killing two of her guards, an incident mentioned in her autobiography.
For many years Clare Hall Hospital was used as a tuberculosis sanatorium. It is now used by Cancer Research UK.
- North Mymms