The name is derived from the French for "beautiful mount" as the parish is located atop an ascent from Fairview and inspired by its clean air and views across Dublin to the Wicklow Mountains. The name was apparently given by Olivia Whitemore and Arthur Guinness in 1764, as they made their new family home in Beaumont House, a protected structure and can be visited today.
Beaumont was originally a farm in the Civil Parish of Coolock, between the townlands of Kilmore Big and Kilmore Little. It is the former home of the Guinness family from 1764-1855. The original 1764 lease between Charles Gardiner and Arthur Guinness can still be seen in the National Library of Ireland. Guinness took 51 acres (210,000 m2) "more or less situate in the Parish of Coolock" on a lease for the longer of 31 years or three lives, and built a house "at Kilmore" ; it is apparent that he later named the property "Beaumont". His rent was £93 p.a.
RTÉ had a radio transmitter in Thorndale, Beaumont (off Beaumont Road, where Collinswood estate is now), from which from 1982 broadcast RTÉ Radio 2 on 1278 kHz AM to the Dublin region, it ceased broadcasting on December 15, 2003. RTÉ used the Beaumont facility to jam radio signals from pirate radio stations in the 1980s.
Beaumont is the location of one of Dublin's main hospitals, Beaumont Hospital, and the Sister of Mercy Convalescent Home. Other facilities include a small group of shops and two pubs.
A former home of Arthur Guinness, Beaumont House, is now a convalescent home for the elderly; there was an ice house on its lands.
Beaumont is also home to the large modern estates, Beaumont Woods - a recent development which houses Beaumont Medical Centre and is located next to Beaumont Hospital - Collinswood, Elm Mount Estate - built in the 1960s - and Ardmore and Montrose.
Beaumont is a parish in the Fingal South East deanery of the Roman Catholic Archdiocese of Dublin, and has a parish church, the Nativity of the Lord Church. There is also a Roman Catholic parish in Whitehall, also taking in the townlands of Santry, Larkhill and to a lesser extent Artane West and Artane South, and part of Artane North, and served by the Church of the Holy Child on the old airport road. This church was blessed by Pope John Paul II as his motorcade passed by during his visit to Ireland in 1979.
An all-girls school, Mercy Beaumont School, founded in 1957, is located beside the hospital. St. Fiachra's Junior and Senior Schools are also located near the hospital and the church, and St. Pauls Special School is also here.
- World-famous brewer Arthur Guinness established his residence in Beaumont, in what is now Beaumont convalescent home.
- Former Chelsea and Republic of Ireland international footballer Paddy Mulligan was born and raised in Beaumont.