You have to be careful here. I realize that in North America the term "league" is a generic reference to any type of sports competition, but in rugby it means something else. There are two forms or rugby. One called rugby "union", which is the more popular worldwide form of the game, but there is also a variation called rugby "League", a regional form of the game which is played in northern England and eastern Australia, but pretty much nowhere else. The two games have evolved into distinctly different forms since they diverged late in the 19th century, and fans of one sort generally hate the other. In Rugby Union, there are four "major" competitions. In the northern hemisphere there is the English Avivia Premieship, made up by the twelve best English clubs. There is also the Pro 12 or "Celtic League", which is also made up of 12 clubs based in Ireland, Wales Scotland and Italy. Finally there is the French Top-14. In the southern hemisphere the main competition is the "Super-15" which has 5 clubs each from New Zealand, Australia and South Africa. There are also two other competition which rival these and have excellent quality rugby -- the ITM Cup in New Zealand and the Currie Cup in South Africa. In Rugby League the only two major club competitions are "SuperLeague" based in in the industrial towns in northern England, and the National Rugby League played in Australia.
If your English; Super League, if your Australian; the NRL.
