Derby is a geographic parish in Northumberland County, New Brunswick, Canada.

[7] The parish was named in honour of the Earl of Derby,[8] Prime Minister of the United Kingdom at the time of its erection.

William F. Ganong notes that local legend states the parish took its name from horse races held in the area.

[8] Derby was erected in 1859 from all of Nelson Parish north of the Southwest Miramichi River[9] plus Beaubears Island.

[10][11][18] italics indicate a name no longer in official use Bodies of water[b] at least partly within the parish.