Cahill, Mabel Esmonde (1863–c.1905), tennis champion, was born 2 April 1863 in Ballyragget, Co. Kilkenny, daughter of Michael Cahill (d. 1877), gentleman landowner and barrister-at-law, of Ballyconra House, Ballyragget, and his second wife, Eliza (née Netterville). Mabel, who was the eleventh child among her father's five daughters and seven sons by Eliza (who left him at some time before his death) and his first wife, Margaret (née Magan), attended school at Roscrea, Co. Tipperary. At least three of her brothers preceded her to America, and were living in California in 1877. She arrived in New York (7 October 1889), aged 26. It appears that she had learned to play tennis in Ireland and that shortly after coming to America she joined the New York Tennis Club.
In 1890 she entered the US Open tennis championships, which had been established at the Philadelphia Cricket Club in 1887. In that era the format of the singles championship saw the defending champion progress automatically to the final, where she would play the winner of a knockout competition played between all other entrants. In 1890 she was defeated by Ellen Roosevelt in the final of the knockout competition. In 1891 she returned to Philadephia and defeated Grace Roosevelt in the knock-out stages, before defeating Ellen Roosevelt to claim the championship, with the local press commenting on her ‘manly style’, especially a heavy forehand. She enjoyed even more success later in that tournament when she joined with Emma Leavitt Morgan to beat the Roosevelt sisters, who were first cousins of Franklin D. Roosevelt (US president 1933–45), in the final of the ladies’ doubles. In 1892 she successfully defended her singles title when she defeated the 16-year-old Elisabeth ‘Bessie’ Moore in the final, who was later to reach eight US Open singles finals, winning four. The match lasted five sets, as womens’ matches were played as the best of five sets at the US Open through the 1890s. She also defended her doubles title, this time in the company of Adeline McKinley, and added the national mixed doubles title when playing with the American Clarence Hobart in 1892. She became the first player to win all three titles in the same year, having already become the first non-American to win a US Open title. She declined to return to Philadelphia for the 1893 championships. In 1976 she was inducted into the International Tennis Hall of Fame and remains the only Irish tennis player to win a US Open championship.
Little is known of her life beyond tennis, though she did write a novel, Men, her playthings, published in New York in 1890 and again the following year by a different publisher. In June and July 1893 she contributed two articles to the Ladies’ Home Journal under the titles, respectively, of ‘The art of playing good tennis’ and ‘Arranging a tennis tournament’. She was later believed to have left America and was reported to have attended the Wimbledon tennis championships in the early 1900s. In honour of her achievements in tennis, the Irish Lawn Tennis Association placed an advertisement in the national press in 1936 asking that she, or one of her representatives, come forward to claim a gold medallion struck to honour her achievements in America; it is not known if the medallion was collected. It is thought that she may have died in Ireland c.1905.