Millsboro is a town in Sussex County, Delaware, United States. Millsboro is part of the Salisbury, Maryland-Delaware Metropolitan Statistical Area.
Millsboro's earliest European settlers were of English family origin; though most were second generation colonists who simply migrated north from the eastern shore of Virginia in order to join in the timber drive of the later seventeenth century, which brought many seeking to cut the vast mixed deciduous forests. The settlement itself was created in the second half of the seventeenth century when settlers from Accomack County, Virginia arrived to cut timber along the drainages. At one time no less than seven lumber mills were present, the largest employing over 70 laborers. These early years are well documented in the annals of Virginia history. The township during the first settlement period, although unincorporated, had several stores, churches, a bakery and various tack and blacksmith shops as well as and both Anglican and Presbyterian congregations. The area has many cemeteries dating from this original settlement period, which is considered the founding of the township, including the Lingo Family Cemetery and others.
A second period of settlement occurred after Elisha Dickerson built a dam on the Indian River in the 1792. There had been a settlement there for nearly a century before this, but the building of the dam was considered the official town establishment. At the time it was called "Rock Hole." The town grew, and more mills were built.