The Boston Thirteens were founded in 2009 as an expansion team of the American National Rugby League (AMNRL). The league had been attempting to form a rugby league team in Boston for several years, due to the comparatively strong presence of rugby union in the area. The Thirteens played in the AMNRL from 2009 & 2010, going to the league semi-finals in their inaugural season. In 2010 they became one of seven teams to depart from the AMNRL in order to found a new governing body: the USA Rugby League (USARL).