Selbyville is a town in Sussex County, Delaware, United States. The population was 2,167 at the 2010 census, an increase of 31.7% over the previous decade. It is part of the Salisbury, Maryland-Delaware Metropolitan Statistical Area.Selbyville traces its history back to its founding in 1778. It was incorporated in 1902.Selbyville was originally known as Sandy Branch due to its location on a branch of that name emanating in the Cypress Swamp at the head of the St. Martin's River. A grist mill and saw mill opened there in the late 18th century. In 1842, Sampson Selby began marking packages for delivery to his country store, Selby-Ville.By 1918, Selbyville was the major supplier of strawberries for the entire east coast, an industry that remained strong until the 1930s.Today, one of its main employers is Mountaire Farms, a poultry company, which runs a processing plant on Hosier Street.