2004–05 Isthmian League

Also, it was the first season after the creation of the Conference North and South, one step above the Isthmian League.

Tonbridge Angels, Dover Athletic and Kingstonian finished bottom of the table and were relegated to Division One, while 19th-placed Cheshunt were reprieved as the club with a better record than the equivalent Northern Premier League and Southern League clubs after Conference South side Hornchurch folded.

Remaining Division One North clubs were transferred to the Southern Football League.

There was no relegation from Division Two, though Abingdon Town resigned from the league at the end of the season.

The eighteen clubs to have made it through the first round were entered into the second-round draw with Fleet Town and Whyteleafe, making twenty teams.