It is one of the oldest rugby league competitions in Australia, founded in 1911 with five clubs (Dapto, Helensburgh, Mount Keira, Unanderra and Wollongong).

Only the Northern parts of the Illawarra have traditionally been included in this competition, with teams further south playing in Group 7.

The Division also supplies players to the NSWRL Harold Matthews and SG Ball Cup competitions.

On 21 July 2011, whilst celebrating their centenary, Illawarra Rugby League announced their "Team of the Century".

The entire team follows: The following table lists the clubs and the teams fielded in the 2024 senior competitions: Mojo Homes Illawarra Cup - NSWRL President's Cup Southern Conference (PC), Division 1 (Div1), Division 2 (Div2), Under 18s (U18), Women's tackle (Wom), Ladies League Tag (LLT).