1989–90 Isthmian League
The 1989–90 season was the 75th season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England.
The league consisted of three divisions. Division Two was divided into two sections.
Slough Town were champions, winning their second Isthmian League title and were promoted to the Conference.The Premier Division consisted of 22 clubs, including 19 clubs from the previous season and three new clubs:
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:
Four clubs promoted from Division Two North:
Four clubs promoted from Division Two South:
Division Two North
Division Two North consisted of 22 clubs, including 19 clubs from the previous season and three new clubs:
Division Two South
Division Two South consisted of 21 clubs, including 18 clubs from the previous season and three new clubs:
