The structure of the Southern League has changed several times since its formation in 1894, and currently there are 87 clubs which are divided into four divisions.

The league has its administrative head office at Eastgate House in Gloucester.

Woolwich Arsenal (nowadays simply Arsenal) were the first club in London to turn professional in 1891 and were one of the prime motivators behind an attempt to set up a Southern League to mirror the existing Northern and Midlands based Football League.

Additionally, an amateur league, the Southern Alliance, was founded in 1892, with seven clubs from the region, but that folded after one incomplete season.

Nonetheless, another attempt was made to form the Southern League, and this time it was successful.

The sixteen original founder members were:[3] 2nd Scots Guards withdrew before the first season started and were replaced by Southampton St Mary's.

Woolwich Arsenal attempted to add their reserve side to the second division but this application was refused due to the club's existing membership of The Football League.

[5] Two Southern League clubs, Southampton (in 1900 and 1902) and Tottenham Hotspur (in 1901) reached the final of the FA Cup around the turn of the twentieth century.

Out of the six meetings the respective league champions had in the Shield, however, only one was won by the Southern League champions – Brighton & Hove Albion, in 1910, and this remains their only top level national honour.

[citation needed] Of the original founder members, seven – Bromley, Gillingham (formerly New Brompton), Luton Town, Millwall, Reading, Southampton and Swindon Town – went on to be Football League clubs.

From the 2020–21 season the league has been sponsored by Pitching In, Entain's grassroots sports investment programme.

For the 1899–1900 season, the league reverted to the old format, after all the members of the South-West section resigned.

For the 1945–46 season, the Midweek Section was not played due to power restrictions after World War II.

For the 1958–59 season the Southern League was again divided into two sections: North-Western and South-Eastern.

The winners of each section contested a playoff for the Southern League championship.

In general, there has been a drift southwards, with clubs in the Midlands moving into the Northern Premier League.