Retford secured a return to the top flight of district cricket, thanks to a rain affected draw against Whitwell on Saturday.
The nine points they picked up at Cricket Field Lane maintained their lead over promotion rivals Firbeck.
Whitwell set a total of 270 for 7, and Retford were 30 for 0 when the game was called off.
In Bassetlaw Division Two, Ordsall Bridon II missed out on the championship by a single point, after a weather draw in the title decider with Grassmoor.
Bridon made 237 for 4, Henry Appleyard starring with 76 runs.
Grassmoor were well set at 141 for 1 as rain halted play, but Bridon still won promotion, finishing second in the table.
Retford II ended the season with a weather draw and took third place in Division Three.
Iain Bates took 4 for 20 as they bowled Bawtry out for 187.
Retford were 42 for 4 in reply when the game ended due to the conditions.