It is contiguous on the east with Ocean View, and bordered on the north, west and south by unincorporated portions of Sussex County.

[10] The early settlement of the Millville area by Europeans is poorly recorded, although it is known that the swampy, marshy nature of much of the land of eastern Baltimore Hundred in southeastern Delaware when the first Europeans arrived led them to establish plantations on higher ground in the vicinity of what are now Millville, Ocean View, and Clarksville.

Millville itself grew up around a steam-powered sawmill operated by Captain Peter Townshend in the late 19th century, becoming a center for lumber, agricultural products, and commercial fishing.

[8] For a time, the names "Dukestown" and "Dukesville" were considered for the town because of the prominence and number of members of the Dukes family who lived in the area.

However, the population more than doubled by the 2010 census, rising to 544 residents,[citation needed] the highest in the recorded history of Millville.