2009–10 Isthmian League

Premier Division

The Premier Division consisted of 22 clubs, including 17 clubs from the previous season, and five new clubs:

Dartford won the division and were promoted to the Conference South along with play-off winners Boreham Wood. Bognor Regis Town were relegated for the second season in a row along with Waltham Abbey, who had only spent one season in the Premier Division. Ashford Town resigned from the league. Margate were reprieved from relegation for the second season in a row, this time after Chester City and Farsley Celtic folded and Grays Athletic were demoted from the Conference Premier to Isthmian League Division One North.

League table

Source:
Rules for classification: 1) points; 2) goal difference; 3) number of goals scored
(C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished:
(Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.

Results grid

Updated to games played on 30 April 2010.
Source: Ryman League Premier Division
1 ^{^} The home team is listed in the left-hand column.
Colours: Blue = home team win; Yellow = draw; Red = away team win.

Division One North

Division One North consisted of 22 clubs, including 17 clubs from the previous season, and five new clubs:

Lowestoft Town won the division and were promoted for the second season in a row along with play-off winners Concord Rangers. Leyton were reprieved from relegation after numerous higher league clubs folded. VCD Athletic were demoted after failing to meet ground grading requirements and returned to the Kent League. Harlow Town were reprieved from relegation after an appeal by VCD was turned down.

After the end of the season Maldon Town merged with Essex Senior League side Tiptree United to form a new club Maldon & Tiptree, who took the place of Maldon Town.

League table

Source:
^† Ilford were deducted nine points for fielding a suspended player in five games between August and January.
^‡ Harlow Town were deducted ten points for entering administration.
Rules for classification: 1) points; 2) goal difference; 3) number of goals scored
(C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished:
(Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.

Results grid

Updated to games played on 30 April 2010.
Source: Ryman League Division One North
1 ^{^} The home team is listed in the left-hand column.
Colours: Blue = home team win; Yellow = draw; Red = away team win.

Division One South

Division One South consisted of 22 clubs, including 19 clubs from the previous season, and three new clubs:

Folkestone Invicta won the play-offs and returned to the Premier Division after two seasons of absence along with Croydon Athletic, who won the division. Walton Casuals and Eastbourne Town finished in the relegation zone but were reprieved due to the resignation of Ashford Town (Kent) and as a knock-on effect from Merthyr Tydfil's expulsion from the Southern League.

League table

Source:
Rules for classification: 1) points; 2) goal difference; 3) number of goals scored
^† Folkestone Invicta were deducted ten points for insolvency.
^‡ Godalming Town were deducted three points for fielding a suspended player against Merstham on 19 September (3–1).
(C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished:
(Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.

Results grid

Updated to games played on 30 April 2010.
Source: Ryman League Division One South
1 ^{^} The home team is listed in the left-hand column.
Colours: Blue = home team win; Yellow = draw; Red = away team win.

League Cup

The Isthmian League Cup 2009–10 was the 36th season of the Isthmian League Cup, the league cup competition of the Isthmian League. Sixty-six clubs took part. The competition commenced on 20 October 2009 and finished on 24 March 2010.

First round

Four clubs from division Ones participated in the First round, while all other clubs received a bye to the Second round.

Second round

The two clubs to have made it through the First round were entered into the draw with every other Isthmian League club, making sixty-four teams.