It is the highest level club division in Scotland, and contains many of the country highest profile clubs. However it is not the highest level of rugby union in Scotland, Edinburgh Rugby and Glasgow Warriors play against Irish, Welsh and Italian teams in the Magners League.
Until the 2009/10 season, the bottom teams were relegated to the Third Division. Since the 2010/11 season, the division merges with the Scottish Premiership Division Two. After 11 matches, the top eight teams in division one play each other in Premier A. The bottom 4 teams join the top 4 teams of division two to form Premier B and the bottom 8 teams of division two form Premier C.