Maine State Route 166 (SR 166) is the principal state road leading northward from the village of Castine, which is located at the end of a large peninsula defined by Penobscot Bay on the west and the Bagaduce River on the east. The village proper is located on the Bagaduce Peninsula, which is separated from the larger peninsula by a neck of land between Wadsworth Cove and Hatch Cove. From this neck, SR 166 runs roughly north-by-northeast, paralleling the Bagaduce River up to a junction with Maine State Route 199. SR 166A runs follows a more northerly course, beginning just north of the neck and paralleling the Penobscot Bay shore. The neck was made a more prominent geographic division of the town during the American Revolutionary War, when British forces occupying Castine dug a canal 10 to 12 feet (3.0 to 3.7 m) wide across it. The British occupation was notable in Castine's history as the focus of the disastrous Penobscot Expedition, an attempt by the state of Massachusetts (which Maine was then part of) to dislodge them. The canal forms the southern boundary of this district.[2]
Stretching northward from the canal on the mainland for about 2 miles (3.2 km), SR 166 is a rural road, along which are eleven houses built between about 1765 and 1830. All but one have fairly typical Federal period styling, and are either 1-1/2 or 2 stories in height, with a gable roof, clapboard siding, and either a large central chimney or a pair of end chimneys. The oldest house, dating to c. 1765, has vernacular Georgian styling. The collection of properties provides a remarkably well-preserved view of what rural Castine looked like 200 years ago.[2]
