The 1997–98 season was the 83rd season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England.
Yeading, Hitchin Town and Oxford City finished bottom of the table and relegated to the First Division.
Aldershot Town won the division and were promoted to the Premier Division along with Billericay Town and Hampton.
Division Two consisted of 22 clubs, including 16 clubs from the previous season and six new clubs: Three clubs relegated from Division One: Three clubs promoted from Division Three: Canvey Island won the division and returned to Division One straight after relegation from it along with Braintree Town and Wealdstone, both achieved the second promotions in two seasons.
Division Three consisted of 20 clubs, including 14 clubs from the previous season and six new clubs: Three clubs relegated from Division Two: Plus: Hemel Hempstead won the division and returned to Division Two straight after relegation along with Hertford Town and Harlow Town.