Leinster League Division One, as the name implies, is the first division of the Leinster League and started in the 1994/95 season. Suttonians, Co. Carlow, Arklow, Mullingar, Garda, Navan, Naas, Wexford Wanderers, Portlaoise, Dundalk and Enniscorthy entered the division through the qualifying matches in the 1993/1994 season. The number of teams in the division was reduced from 14 to 12 in the 2007/08 season, but this was reversed in the 2008/09 season.