[4] By 1632 the community was protected by Fort William and Mary on today's New Hampshire side of the river; in 1689 defensive works that later became Fort McClary in Kittery Point were added on today's Maine side to the north.

"[5] It was named after the birthplace of a founder, Alexander Shapleigh, from his manor of Kittery Court at Kingswear in Devon, England.

Shapleigh arrived in 1635 aboard the ship Benediction, which he co-owned with another prominent settler, Captain Francis Champernowne,[6] a cousin of Sir Ferdinando Gorges, lord proprietor of Maine.

[7] Together with the Pepperrell family, they established fisheries offshore at the Isles of Shoals, where fish were caught, salted, and exported to Europe.

[8] Thomas Spencer, Esquire, immigrant from Gloucestershire, England, is also a notable settler of Kittery with his wife Patience Chadbourne.

Their story is included in The Maine Spencers: a history and genealogy, with mention of many associated families.'

Located opposite Portsmouth, New Hampshire, the town developed into a center for trade and shipbuilding.

The site supported the lucrative fur trade with Indians, but had the risks of living isolated in the wilderness.

[9] Small became the largest property owner in the history of Maine, and was known as "the great landowner".

"[14] In 1705, during Queen Anne's War, tribes of the Wabanaki Confederacy raided the town, killing six residents and taking five prisoners.

[15] During the Revolution, the first vessels of the U.S. Navy were constructed on Badger's Island, including the USS Ranger (1777) commanded by John Paul Jones.

The Portsmouth Naval Shipyard, the nation's first federal navy yard, was established in 1800 on Fernald's Island.

From 1946 and 1977, when racial discrimination in public accommodations was common, Clayton and Hazel Sinclair operated the Rock Rest summer guest house in Kittery Point providing lodging to Black vacation travelers.

[28] The town in 2024 approved the removal of one of the shopping plazas, The Outlets at Kittery, to be replaced with apartment housing, a hotel, and a restaurant.

[29] Kittery Foreside is a popular, walkable neighborhood adjacent to the Portsmouth Naval Shipyard that has many commercial businesses, including boutique shops, restaurants, and cafes.

It also features historic homes, large shade trees, and a number of arts and culture organizations.

[31] In 2023, the Portland Press Herald reported that Kittery has the highest per capita number of vegan and vegetarian restaurants and food businesses in Maine.

[32] In Kittery, coastal property, shoreland infrastructure, and the Portsmouth Naval Shipyard are all vulnerable to rising seas caused by the changing climate.