Millville is a town in Sussex County, Delaware, United States. The population was 544 at the 2010 census, an increase of 110% from the previous decade. It is part of the Salisbury, Maryland-Delaware Metropolitan Statistical Area and lies within Baltimore Hundred.
Millville is located at 38°32′58″N 75°07′24″W (38.5495569, -75.1232391), approximately 1 mile (2 km) west of the Atlantic Ocean and about 1 mile (2 km) south of Indian River Bay. It is contiguous on the east with Ocean View, and bordered on the north, west and south by unincorporated portions of Sussex County.
According to the United States Census Bureau, the town has a total area of 0.5 square miles (1.3 km2), all land.
At the 2000 census, there were 259 people, 111 households and 71 families residing in the town. The population density was 534.1 per square mile (208.3/km2). There were 141 housing units at an average density of 290.8 per square mile (113.4/km2). The racial make-up of the town was 96.91% White, 1.93% from other races, and 1.16% from two or more races. Hispanic or Latino of any race were 0.77% of the population.