Nunn is a Statutory Town in Weld County, Colorado, United States. The population was 504 at the 2020 census.
A post office called Nunn has been in operation since 1905. The town was named after Tom Nunn, who was credited with preventing a nearby train wreck.
Nunn is located at . According to the United States Census Bureau, the town has a total area of , all of it land.
Nunn is the home of Greenfaith Ministry, the nation's first cannabis sacrament church and charity.
About a third of the town's budget is generated by citations written by its police department.