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.

[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.