This house, which at the time of building "was scarcely surpassed by any private residence in New England," was built by Captain Archibald MacPheadris, native of Scotland, member of the King's Council in 1722, and a prominent merchant. He was a leader in the first iron works in America, when the Lamprey River Iron Works were established under charter from the general court of Massachusetts in 1719, with a grant of land two miles wide at the Dover line. It is interesting to note that this land came into the possession of the town of Portsmouth as a result of the town's liberal contribution to Harvard College in 1672, after the burning of the library. In 1719, for the purpose of obtaining fuel, and for providing residences for workmen, whom the company intended to secure in Europe, the town asked an order from the General Court "for laying out the six mile square of land at the head of Oyster River, formerly granted by Massachusetts to the town of Portsmouth." The location of the land and the ancient business venture are preserved in the name of Gilmanton Iron Works.

This mansion was commenced in 1718 and finished in 1723 at an expense of 6,000 pounds. The brick used in the construction of the eighteen-inch walls was brought from Holland, with other of the materials. Marrying Sarah, one of the sixteen children of Lieutenant Governor John Wentworth, Captain MacPheadris lived in his house but six years, for in 1729 he died, leaving a daughter, Mary. She married in 1754, Honorable Jonathan Warner, who was King's Councillor until the Revolution annulled his commission.

The hall of the house has most interesting frescoes of unknown origin, representing various subjects; Governor Phipps on his charger, a lady at a spinning-wheel, a representation of Abraham offering up Isaac, and numerous others, which were covered by four layers of wall paper, and were accidently discovered about i850, when the removal of a small piece of the covering revealed a painted horse's hoof. In the hall hang enormous elk antlers presented to Captain MacPheadris by his Indian friends while portraits of two Indians are supposed to picture the hunters with whom the first owner dealt in furs. "The lightning rod on the west end of the house was put up in 1767 under the personal inspection of Doctor Benjamin Franklin, and was probably the first put up in New Hampshire."

UPDATE: The Warner House is now an independent House museum.