Governor John Langdon House, at 143 Pleasant St. on the Portsmouth Harbour Trail, was built in 1784 by John Langdon, a three-time governor of the state, signer of the Constitution and first president of the Senate. In 1789 George Washington described the Georgian mansion as “the finest house in Portsmouth.”
The main portion of the structure retains its original balustrade and stately portico. Ornate woodwork and period furniture highlight the interior; there are rotating exhibitions on the first floor. Behind the house is an enclosed garden with a rose arbor and pavilion.