Drumthwacket ( ) is the official residence of the governor of New Jersey. The mansion sits at 354 Stockton Street in Princeton, near the state capital of Trenton. It is one of only four official governor's residences in the country not located within their respective state capitals; the others are in Wisconsin, Ohio, and Tennessee. Built in 1835 and expanded in 1893 and 1900, Drumthwacket was sold with its surrounding land to the state in 1966. Drumthwacket was added to the National Register of Historic Places on June 10, 1975, for its significance in agriculture, architecture, commerce, landscape architecture, and politics. It was designated the governor's mansion in 1982. The estate is administered by the New Jersey Department of Environmental Protection. In addition to being an executive residence, the house is also a historic house museum. History The Colonial era mansion of the governors of New Jersey, Proprietary House, is located in Perth Amboy. The land that it is built upon was once owned by William Penn, the Quaker proprietor of the Province of Pennsylvania and founder of Philadelphia. William Olden acquired the property in 1696, and a small white homestead by Stockton Street called Olden House was later built on it. In 1799 Charles Smith Olden was born there. Olden gained wealth working at a mercantile firm in Philadelphia and later New Orleans before returning to Princeton, where in 1835 he began to build Drumthwacket, taking its name from two Scottish Gaelic words meaning "wooded hill". Olden began his involvement in politics as a gentleman farmer and businessman, as treasurer and Trustee of the College of New Jersey (now Princeton University), as a state Senator, and finally in 1860 as governor, the first to live at Drumthwacket. The original structure consisted of a center hall with two rooms on each side, including the -story center section and large portico with six Ionic columns, which remains today. In 1893, financier, industrialist, and Princeton University benefactor Moses Taylor Pyne purchased Drumthwacket for the sum of $15,000 from Olden's widow. Pyne was responsible for major expansions of the home, turning it into a magnificent estate, "surpassing anything previously built in Princeton". Pyne's huge wealth allowed him to add two wings on each side of the house, in 1893 and 1900, both designed by Raleigh C. Gildersleeve (who also designed many Princeton University buildings) and including a paneled library. Pyne also added park-like