In 1623, brothers William and Edward Hilton settled at Pomeroy Cove on Dover Point, near the confluence of the Bellamy and Piscataqua rivers.

William Hilton built a salt works on the property (salt-making was the principal industry in his hometown of Northwich, England).

In 1633, the plantation was bought by a group of English Puritans who planned to settle in New England, including Viscount Saye and Sele, Baron Brooke and John Pym.

But Lord Saye and Sele's group lost interest in their settlements, both here and at Saybrook, Connecticut, when their plan to establish a hereditary aristocracy in the colonies met disfavor in New England.

It was revenge for an incident on September 7, 1676, when 400 Native Americans were tricked by Major Richard Waldron into performing a "mock battle" near Cochecho Falls.

Local Native Americans deemed innocent were released, but considered the deception a dishonorable breach of hospitality.

During Father Rale's War, in August and September 1723, there were Indian raids on Saco, Maine, and Dover, New Hampshire.

So in 1827 the Cocheco Manufacturing Company was founded (the misspelling a clerical error at incorporation),[11] and the next year, the mill was the site of the first women's strike in the United States.

[12] Expansive brick mills were constructed downtown, linked to receive cotton bales and ship finished cloth when the railroad arrived in 1842.

Incorporated as a city in 1855, Dover for a time became a leading national producer of textiles, the mill complex dominating the riverfront and employing 2,000 workers.

In 1922, it was affected by the 1922 New England Textile Strike, shutting down the mills in the city over an attempted wage cut and hours increase.

[14][15] During the Great Depression, however, textile mills no longer dependent on New England water power began moving to southern states in search of cheaper operating conditions, or simply went out of business.

Now called the Cocheco Falls Millworks, its tenants include technology and government services companies, plus a restaurant, brewery and bar.

Small businesses moved into the mills, such as restaurants, toy stores, real estate offices, and barber shops.

[18][19] In early May 2021, waypoint signs were sporadically added to help drivers and walkers navigate Dover with the expansions that are underway.

Long Hill, elevation greater than 300 feet (91 m) above sea level and located 3 miles (5 km) northwest of the city center, is the highest point in Dover.

The Cooperative Alliance for Seacoast Transportation (COAST) operates a publicly funded bus network in Dover and surrounding communities in New Hampshire and Maine.

[23] Wildcat Transit, operated by the University of New Hampshire, provides bus service to Durham, which is free for students and $1.50 for the public.

Saint Mary Academy, a Catholic school, has been in downtown Dover since 1912, currently serving about 200 students from pre-kindergarten to 8th grade.

Portsmouth Christian Academy is located west of the Bellamy River in Dover, serving preschool through 12th grade.

No Republican presidential nominee has carried Dover since George H. W. Bush's five-point victory in the town over Michael Dukakis in 1988.

Dover was the birthplace of the Teenage Mutant Ninja Turtles franchise, created by comic book writers Kevin Eastman and Peter Laird and first published by Mirage Studios—then based in Dover—in 1984.