Beaumont (McGavock), Máirín (Mary) (1894–1972), teacher and nationalist, was born 7 December 1894 in Glenarm, Co. Antrim, one of the four daughters of William McGavock, a merchant, and Annie McGavock , a sister of Eoin MacNeill (qv). Máirín's sister Roisín married Joseph Connolly (qv). Educated at the Dominican College, Eccles St., Dublin, she went on to study at UCD, graduating with a first-class BA in languages in 1915. The following year she received an MA in German, and in 1917 she obtained a higher diploma in education. She was influenced by the teaching of Fr Timothy Corcoran (qv), professor of education at UCD.
Máirín McGavock was attending UCD and living at Dominican Hall, Dublin, when she became actively involved with physical-force nationalism. In 1915 she stored some arms and ammunition at Dominican Hall at the request of J. J. ‘Ginger’ O'Connell (qv); she also attended first aid instruction prior to the rising. She was in Antrim when the rising began and took no part, but she participated in prison support and Cumann na mBan activities in the aftermath. During the 1918 general election she canvassed for Desmond FitzGerald (qv) in the Pembroke constituency, and he used her flat as a safe house in November 1920. In the same year she joined the executive of Cumann na mBan. She worked as an organiser for Cumann na mBan in the Louth/Armagh area in 1920–21.
In 1917 she was on the founding staff of Louise Gavan Duffy's (qv) Scoil Bhríde. She was an external examiner in education in the NUI. In 1923 she married the journalist and academic Sean Beaumont (d. 1959), founder of An tEireannach, who later worked on the editorial staff of the Irish Press. They lived in Merrion, Dublin, and had one son and two daughters, one of whom, Máire, married Dónall Ó Móráin (qv).
After independence she was involved in a number of social action and women's associations. In the early 1930s, along with other prominent women nationalists, she was a member of the Dublin Playgrounds Committee, an organisation which ran play and childcare facilities under the aegis of the Civics Institute. She was president of the National University Women Graduates Association in 1951–2 and president of the UCD branch. A member and executive member of the Irish Countrywomen's Association in the 1950s and 1960s, she lectured during that period to ICA courses on Irish literature. As vice-chair of the ICA 'residential courses sub-committee' founded in January 1953 to establish a residential college (renamed the Grianán committee), she participated in talks with the Kellogg Foundation seeking financial support for the project. She chaired the committee session at which a hotel in Termonfeckin, Co. Louth, was chosen as the eventual location of An Grianán. The building was purchased with money awarded by the Kellogg Foundation.
She died 19 January 1972 at St Vincent's hospital, Dublin; her body was donated to the College of Surgeons. Her personal papers are held by Mr P. Beaumont, Dublin, and a photograph of her in Cumann na mBan uniform is held by Helen Ó Ciosáin, Dublin.