1991–92 Isthmian League

The 1991–92 season was the 77th season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England.

For the first time league consisted of four divisions after at the end of the previous season Division Two North and the Division Two South were merged into single Division Two and also Division Three was formed.

Premier Division
The Premier Division consisted of 22 clubs, including 19 clubs from the previous season and three new clubs:
 * Bromley, promoted as runners-up in Division One
 * Chesham United, promoted as champions of Division One
 * Sutton United, relegated from Football Conference

At the end of the season Dagenham merged into Conference side Redbridge Forest to form new club Dagenham & Redbridge. Thus, Bognor Regis Town was reprieved from relegation.

Division One
Division One consisted of 22 clubs, including 16 clubs from the previous season and six new clubs:

Two clubs relegated from the Premier Division:
 * Barking
 * Leyton-Wingate

Two clubs promoted from Division Two North:
 * Stevenage Borough
 * Vauxhall Motors

Two clubs promoted from Division Two South:
 * Abingdon Town
 * Maidenhead United

At the end of the season Harlow Town left the league due to problems with their ground and missed the next season not joining any other league.

Division Two
Division Two consisted of 22 clubs, including 18 clubs from the previous season's Division Two North and Division Two South and four clubs relegated from Division One:

Clubs relegated from Division One:
 * Lewes
 * Metropolitan Police
 * Southwick
 * Worthing

Clubs transferred from Division Two North:
 * Barton Rovers
 * Berkhamsted Town
 * Billericay Town
 * Hemel Hempstead
 * Purfleet
 * Saffron Walden Town
 * Rainham Town
 * Ware
 * Witham Town

Clubs transferred from Division Two South:
 * Banstead Athletic
 * Egham Town
 * Harefield United
 * Hungerford Town
 * Leatherhead
 * Malden Vale
 * Newbury Town
 * Ruislip Manor
 * Southall

Division Three
At the end of the previous season Division Two North and Division Two South were merged resulting in creation of Division Three.

Division Three consisted of 21 clubs, including 20 clubs from the previous season's Division Two North and Division Two South and one new club:

Club joined from the South Midlands League:
 * Thame United

Clubs relegated from Division Two North:
 * Clapton
 * Collier Row
 * Edgware Town
 * Hertford Town
 * Hornchurch
 * Kingsbury Town
 * Royston Town
 * Tilbury
 * Tring Town

Clubs relegated from Division Two South:
 * Bracknell Town
 * Camberley Town
 * Chertsey Town
 * Cove
 * Eastbourne United
 * Epsom & Ewell
 * Feltham
 * Flackwell Heath
 * Hampton
 * Horsham
 * Petersfield United

Before the season started Feltham merged with the Hellenic League side Hounslow to create Feltham & Hounslow Borough F.C.