Dover is a city in Strafford County, New Hampshire, United States. The population was 29,987 at the 2010 census, the largest in the New Hampshire Seacoast region and the 4th largest city in the state of New Hampshire. The population was estimated at 32,191 in 2019. It is the county seat of Strafford County, and home to Wentworth-Douglass Hospital, the Woodman Institute Museum, and the Children's Museum of New Hampshire.
First recorded in its Latinised form of Portus Dubris, the name derives from the Brythonic word for waters (dwfr in Middle Welsh). The same element is present in the town's French (Douvres) and Modern Welsh (Dofr) forms.
The first known European to explore the region was Martin Pring from Bristol, England, in 1603. In 1623, William and Edward Hilton settled Cochecho Plantation, adopting its Abenaki name, making Dover the oldest permanent settlement in New Hampshire, and seventh in the United States. One of the colony's four original townships, it then included Durham, Madbury, Newington, Lee, Somersworth and Rollinsford.
The Hiltons' name survives at Hilton Park on Dover Point (which was originally known as Hilton Point), where the brothers settled near the confluence of the Bellamy and Piscataqua rivers.