The historic Kelley House in Edgartown, among the oldest hotels in the country, was sold Friday to Blue Flag Partners, a Boston-based real estate private equity firm, for $19.6 million.

The 57-room boutique hotel will be operated by Life House, a hotel management company whose portfolio includes luxury hotels on Nantucket and in Denver, Miami and Miami Beach, according to a press release.

“As New England locals with deep personal ties to Martha’s Vineyard, we are honored for the opportunity to steward such a prominent and historic property as the Kelley House, located in the heart of downtown Edgartown,” Jason Brown, a partner at Blue Flag, said in the release.

Dating to the Island’s whaling era, the hotel has been operating almost continuously since the 1740s, though it has had various changes of name and ownership over the years as well as expansions. Originally called the Tavern, it was later known as the Marcy House, the Vineyard House, the Seaview House and the Great Harbour Hotel before reverting to the name it was given around the turn of the 20th century by owners William and Elizabeth A. Kelley.

Real estate records filed Friday show that 23 Kelley Street LLC paid $19.64 million for the property, which is composed of five parcels: 6 and 24 Kelley street, 55 North Water street, 30 Winter street and 51 North street. In addition to several buildings, the hotel includes the pub-style restaurant The Newes from America, a pool and the Wave Bar.

It last sold in 2014 for $8.875 million to a private investment group, PS Kelley LLC of Greenwich, Conn., according to real estate records.

The transaction represents the fourth collaboration between Blue Flag and Life House, which is based in New York, the release said.