The Society operates several historic sites, including the Old Lighthouse Museum and Captain Palmer House. The 1823 Old Lighthouse Museum's six rooms of exhibits testify to the history of this coastal region through exhibits depicting the lives of Stonington's fishermen and farmers, merchants and shipbuilders, pottery makers, blacksmiths, and many other trades. Each year a special aspect of Stonington history is featured. One room with a large dollhouse is reserved for items of interest to children and adults. The 1852 Captain Palmer House displays memorabilia pertaining to Nathaniel's discovery of Antarctica and the Palmer brothers' adventurous lives, as well as other Stonington family portraits, furnishings, and artifacts.

The society offers research library access, lectures, workshops, and educational and recreational events and programs; the museum and house offer exhibits and tours.

The luxurious lifestyle enjoyed by two wealthy 18th-century Connecticut Valley families—until their fortunes collapsed—is displayed in the Phelps-Hatheway House and Garden. Merchant Shem Burbank built the house in 1761. As a Tory sympathizer, his business suffered during the American Revolution. In 1788 he sold the house to Oliver Phelps, who in 1794 flaunted the riches earned from land investments in western New York by adding a wing, an architectural masterpiece that still features original Paris-made wallpaper. Eight years later Phelps left Suffield, bankrupted by his failed land schemes. The house is furnished with outstanding 18th-century Connecticut furniture and landscaped with formal flower beds. The Hatheway family owned the house throughout the 1800s, accumulating an attic full of artifacts that document life during that century.

The house offers tours.

The enduring fame of the Old North began on the evening of April 18, 1775, when the church sexton, Robert Newman, climbed the steeple and held high two lanterns as a signal from Paul Revere that the British were marching to Lexington and Concord by sea and not by land. The Old North Church is officially known as Christ Church in the City of Boston. It was built in 1723, and is the oldest standing church building in Boston. In 1775, on the eve of Revolution, the majority of the congregation were loyal to the British King and many held official positions in the royal government, including the Royal Governor of Massachusetts, making Robert Newman's loyalty to the Patriot cause unusual.

The church offers tours and occasional recreational and educational events and performances.

The Society was formed in 1972 to perpetuate the mission of preserving the rich history of Jericho, Vermont, and the legacy of Wilson "Snowflake" Bentley. The Society's 1885 headquarters is located in the historic Chittenden Mills, a national historic site. The Old Red Mill, as it is known, houses a milling museum, art gallery, craft shop, and is also the home of the "Snowflake" Bentley Exhibit. Native son, Wilson A. Bentley, pioneered the technique of photomicrography and was the first person to photograph a single snowflake. The entire lower level of the building displays priceless mementos of "Snowflake" Bentley, original milling machinery, and the products of Jericho's water-powered mills.

The mill offers exhibits and tours.

The Society is committed to the preservation and interpretation of Arrowhead, home of author Herman Melville, the first National Historic Landmark to be so designated in Berkshire County. The author's study, piazza, the original fireplace from his short story "I and My Chimney" and the restored barn in which Melville and Hawthorne spent hours discussing their writings are all open to the public. The Society has also restored the North Meadow preserving the view of Mount Greylock which was a major inspiration to Melville.

The society offers research library access and occasional recreational and educational events; the museum offers exhibits and tours.

The Mystic River Historical Society, founded in 1973, owns an ever-growing collection of Mystic-related historical books, maps, photographs, and other documents and artifacts contributed by the community. It houses these collections in the William A. Downes Archives Building, erected by the Society specifically to provide a safe environment for them. It maintains part-time archival and curatorial staff available to assist researchers and to continue the organization and cataloging of the collections. In addition to the Downes Building, the Society owns the 1839 Portersville Academy, purchased from the Town of Groton in 1975 and partially restored. This historical building serves as the Society's education and outreach space. A schoolroom of the 1840s has been recreated upstairs, and historical displays form a backdrop for educational activities downstairs.

The society offers exhibits, lectures, tours, research library access, and educational programs.

The Museum is housed in the U.S.'s first academy for African-American women, which operated from 1833–1834. The school was run by Prudence Crandall (1803–1890), today designated as Connecticut's state heroine. The museum includes period rooms, changing exhibits, and a small research library.

The museum offers exhibits, research library access, and educational and recreational programs.

The Society operates a museum housing a collection of furnishings and artifacts ranging from pre-Columbian stone tools and the 1652 Metcalf great chair (the oldest dated American-made chair) to a collection of Dedham and Chelsea pottery. On exhibit are several rare and important clocks including one of the only two known "astronomical shelf clocks" by Simon Willard. Also in the collection are Civil War artifacts and a number of paintings by artists including John Constable, Gilbert Stuart, Amasa Hewins, Henry Hitchings, and Alvan Fisher. Photographic materials document life in Dedham since the 19th century, while furniture and memorabilia bring the past to life. The Society also owns the largest collection of silver by Katherine Pratt, silversmith.

The museum offers exhibits exhibits, tours, and educational programs; the society offers lectures and research library access.

The Society maintains the 1717 Reverend Daniel Putnam House as a museum. Volunteer tour guides, dressed in period costume, explain how daily chores were accomplished in the 1700s, and often cook popular dishes of the day over the kitchen fire.

The house offers tours.

Hearthside is a unique stone mansion built in 1810 on pastoral Great Road, the first road through the wilderness between Providence and Mendon, MA, and one of the oldest thoroughfares in America. Complimenting the historical site is the adjacent Hannaway Blacksmith Shop.

The homestead offers tours, demonstrations, and recreational and educational events.