According to the club's official centenary book, "Abertillery Rugby Football Club", Abertillery were founded on 21 September 1883 in a local public house, "The Prince of Wales". Like many towns and villages in Wales in the late 1880s, Abertillery was home to multiple rugby teams; these included Abertillery Town, Abertillery Harlequins, Abertillery Wednesdays, Heart of Oak and Abertillery Rovers. Abertillery FC and another local team from Abertillery amalgamated around September 1887 into a single club called "Abertillery Football Club". These clubs had periods of growth and decline until two main teams emerged, Abertillery Town and Harlequins; these two sides merged into a single club known as Abertillery RFC in 1901. The early clubs did not originally own a match pitch of their own, so relied on sympathetic landowners to let them play on vacant fields. These included the Gas Works Field and Old Barn Field. The club also did not possess a club-house, so from 1890 they used Wilkinson's Temperance Hotel.