The Irish Football League (IFL) is a league of football (soccer) clubs in Northern Ireland. It should not be confused with the Football League of Ireland, which is the league for the Republic of Ireland.
The IFL was originally formed as the football league for all of Ireland in 1890 (although most of its member clubs were in fact based in the north), but became the league for just Northern Ireland in 1921 upon partition, with a separate league and association (the Football Association of Ireland) being formed for the Irish Free State in the south.
The IFL's records from its days in operation as the league for all of Ireland still stand as the records for Northern Ireland (as is the case for the Northern Ireland national football team).
The IFL is split into three divisions, the Premier, First and Second, with promotion and relegation between them at the end of each season. This is a change from the way in which it used to operate until recently, as a single division entity.