Trimountain

Boston's central hill once had three summits. In 1634 William Wood described, north-west of the town, "a high Mountaine with three little rising Hills on the top of it, wherefore it is called the Tramount," the source of the names Trimountain and Tremont. The middle peak, first called Sentry Hill and later Beacon Hill, carried a town plot six rods square reserved for a beacon in 1634-35, and stood perhaps 60 feet higher than the ground beside the present Beacon Hill Monument. In 1800 the Reverend John Lathrop gave its height as 138 feet 6 inches above the sea. In 1811 the town, short of money, sold the summit plot for $9,300, and the buyers at once dug the cone down to the level of the new State House, taking down Charles Bulfinch's 1790 monument. The western peak, Mount Vernon, had already gone: from 1803 the Mount Vernon Proprietors, Harrison Gray Otis among them, carted it into the river to make the land along Charles Street, using an inclined gravity railway that the conveyancer Nathaniel Ingersoll Bowditch later called the first railroad used in the country. The 1811 digging undermined William Thurston's house, which by his account was left on a cut some 60 feet deep and had to be taken down; his suit, Thurston v. Hancock, became a celebrated case in property law. Beacon Hill gravel also filled the Mill Pond. Temple Street was extended across the old summit in 1820. The eastern peak, Cotton Hill, was cut down by 65 feet in 1835 for Pemberton Square, and the ridge between the peaks was levelled about ten years later.