FRANKFORT, (180 alt.; Frankfort Town, 468 pop.), a village shaded by huge century-old elms, belies its history of industrial prosperity. Log cabins first appeared here in 1756, and a permanent settlement was made in 1760. Shipbuilding began early and, by the time of the Revolution, Frankfort was important enough to draw the attention of the British Navy. Many of the 33 ships destroyed along the Penobscot in 1779 were tied up, or under construction, in this port. The English bombarded the settlement in 1814, subsequently occupying it. Left from Prospect on State 174 is FORT KNOX (see illustration), 2.5 m., now a State reservation. The site for this fort was selected during the days of the heated boundary disputes with Great Britain, but work was not begun until 1846; the fort was never entirely completed, though troops were trained here during the Civil War. This massive structure was built of Mt. Waldo granite and commands one of the most beautiful views on the Penobscot River.