The Third Division North of the Football League was a tier in the English football league system from 1921 to 1958. It ran in parallel with the Third Division South with clubs elected to the League or relegated from a higher division allocated to one or the other according to geographical position. Some clubs in the English Midlands shuttled between the Third Division North and the Third Division South according to the composition of the two leagues in any one season.
The Third Division South had been formed in the 1920-21 season (as simply the Third Division) with 22 teams drawn mostly from the Southern League. It was decided that this gave the Football League as a whole too much of a southern bias, so the Third Division North was created in 1921-22 to redress the balance. had finished bottom of the Second Division at the end of the 1920-21 season, and they were relegated into this new division, where they joined Grimsby Town who had spent a season in the Third Division after relegation from the Second Division in 1919-20. As there was no Northern equivalent of the Southern League, the remaining 18 teams came from several regional leagues: the Midland League, the Central League, the North Eastern League, the Lancashire Combination and the Birmingham Combination.
The original 20 teams were: , Darlington, Grimsby Town, Hartlepools, Accrington Stanley, Crewe Alexandra, Stalybridge Celtic, Walsall, Southport, Ashington, Durham City, Wrexham, Chesterfield, Lincoln City, Barrow, Nelson, Wigan Borough, Tranmere Rovers, Halifax Town and Rochdale. The division was extended by a further two teams in 1923 to take the total to 22, and for the 1950-51 season the division was expanded to 24 clubs, with Scunthorpe United and Shrewsbury Town joining.