Notts, Lincs & Derbyshire 4 was a tier 13 English Rugby Union league with teams from Nottinghamshire, Lincolnshire and Derbyshire taking part. Promoted teams moved up to Notts, Lincs & Derbyshire 3 and since the cancellation of Notts, Lincs & Derbyshire 5 at the end of the 1991–92 season there was no relegation. Notts, Lincs & Derbyshire 4 was cancelled at the end of the 1995–96 campaign and the majority of teams transferred into Notts, Lincs & Derbyshire 3.
The original Notts, Lincs & Derbyshire 4 was divided into two tier 10 divisions - East and West. Promotion was to Notts, Lincs & Derbyshire 3 and there was no relegation until Notts, Lincs & Derbyshire 5 was introduced ahead of the 1990–91 season.
For the 1990–91 season Notts, Lincs & Derbyshire 4 was restructured became a single tier 10 league. Promotion continued to Notts, Lincs & Derbyshire 3 and relegation was now to the newly introduced Notts, Lincs & Derbyshire 5.
Restructuring of the Midlands leagues saw Notts, Lincs & Derbyshire 4 drop two levels to become a tier 12 league. Promotion continued to Notts, Lincs & Derbyshire 2 and the cancellation Notts, Lincs & Derbyshire 5 meant there was no longer relegation.
The top six teams from Midlands 1 and the top six from North 1 were combined to create National 5 North, meaning that Notts, Lincs & Derbyshire 4 dropped another level to become a tier 13 league. Promotion continued to Notts, Lincs & Derbyshire 3 and there was no relegation. At the end of the 1995–96 season the division was discontinued and the majority of clubs transferred to Notts, Lincs & Derbyshire 3.
^The cancellation of Notts, Lincs & Derbyshire 5 at the end of the season, combined with the promotion of all clubs in the division, meant there was no relegation.
^Runners up Bolsover would drop out of the leagues at the end of the season. All other teams would be transferred into Notts, Lincs & Derbyshire 3 due to restructuring.
^One of Cleethorpes titles was for Notts, Lincs & Derbyshire 4 East.
^Ashbourne's title was for Notts, Lincs & Derbyshire 4 West.