Neptune Beach is a beachfront city east of Jacksonville in Duval County, Florida, United States. When the majority of Duval County communities consolidated with Jacksonville in 1968, Neptune Beach, along with Jacksonville Beach, Atlantic Beach and Baldwin remained quasi-independent. Like those other municipalities, it maintains its own municipal government but its residents vote in the Jacksonville mayoral election and are represented on the Jacksonville city council. As of the 2020 census, the population is 7,217. Neptune Beach is the smallest of the Jacksonville Beaches communities.

Jacksonville is the most populous city proper in the U.S. state of Florida, located on the Atlantic coast of northeastern Florida. It is the seat of Duval County, with which the City of Jacksonville consolidated in 1968. It is the largest city by area in the contiguous United States as of 2020.