Passamaquoddy Bay

45°05′N 67°05′W / 45.083°N 67.083°W / 45.083; -67.083

Passamaquoddy Bay (French: Baie de Passamaquoddy) is an international inlet of the Bay of Fundy located between southwestern New Brunswick in Canada and southeastern Maine in the United States, at the mouth of the St. Croix River.^[1][2] The bay is defined by a complex coastline of islands, headlands, and narrow passages, including Campobello Island and Deer Island, and connects to the open Bay of Fundy through constricted channels such as Head Harbour Passage and Quoddy Narrows.^[3]

The bay lies within the traditional territory of the Passamaquoddy (Peskotomuhkati) and other Wabanaki peoples and has been used for millennia for fishing, travel, and settlement. French colonists established an early European settlement on Saint Croix Island in 1604. During the eighteenth and early nineteenth centuries, the bay’s position along an evolving international boundary contributed to disputes over sovereignty, navigation, and trade, which were largely resolved by boundary agreements concluded in 1908 and 1910.

From the late eighteenth century through the nineteenth century, Passamaquoddy Bay was a notable centre of cross-border smuggling, particularly during periods of trade restriction such as the Jeffersonian embargo and the War of 1812. Today, the bay remains important for fisheries, aquaculture, marine research, and regional navigation, and is recognised for its ecological significance within the outer Bay of Fundy–Gulf of Maine system.

Passamaquoddy Bay forms part of the southwestern Bay of Fundy and the northeastern margin of the Gulf of Maine. The bay’s mouth is partly enclosed by a chain of islands—most prominently Deer Island and Campobello Island—which regulate water exchange between the bay and the open Fundy system.^[2] The coastline is deeply indented, with numerous coves, shoals, and narrow channels.

Navigation into and through the bay uses a series of named passages, including (from south to north and westward into the St. Croix system) Quoddy Narrows, Lubec Channel, Friar Roads, Western Passage, and Head Harbour Passage.^[3] Head Harbour Passage, between Campobello Island and Deer Island, provides the principal deep-water entrance to the bay and the St. Croix River approaches.

Oceanographic studies commonly treat Passamaquoddy Bay and its approaches as part of the broader “Quoddy Region”, characterised by strong semidiurnal tides and vigorous tidal exchange with the Bay of Fundy.^[4][5]

Long-term monitoring by Fisheries and Oceans Canada has documented pronounced seasonal variation in temperature and salinity in Passamaquoddy Bay and its approaches, influenced by tidal mixing, freshwater input from the St. Croix River, and exchange with offshore waters.^[6]

Passamaquoddy Bay forms part of the Quoddy Region, an area identified by the Government of Canada as having ecological and biological significance within the outer Bay of Fundy system.^[7]

These ecological conditions support productive marine habitats and underpin fisheries, aquaculture, and seabird populations. Passamaquoddy Bay has also been a focus of long-term biological and environmental research, particularly through studies associated with the St. Andrews Biological Station.^[6]

Passamaquoddy Bay lies within the broader Wabanaki, or “Dawnland”, region of northeastern North America. Ethnohistorical scholarship identifies the bay as part of the traditional territory of the Passamaquoddy (Peskotomuhkati) people, whose name for the bay forms the basis of the English toponym “Passamaquoddy”.^[1][8]

Archaeological evidence indicates long Indigenous occupation and use of the bay’s shores and nearby river corridors prior to European contact. The bay’s sheltered waters and access to inland waterways such as the St. Croix River supported fishing, seasonal settlement, and regional travel within the Wabanaki world.

The first documented European settlement in the Passamaquoddy Bay region occurred in 1604, when a French expedition led by Pierre Dugua, Sieur de Mons established a short-lived colony on Saint Croix Island in the St. Croix River.^[9][10]

Ambiguities in the boundary between the United States and British North America in Passamaquoddy Bay persisted into the nineteenth century despite provisions of the Treaty of Ghent (1814). These issues were largely resolved by agreements concluded in 1908 and 1910, which defined the international boundary through the bay as a series of straight-line segments extending toward the Grand Manan Channel.^[11]

A related modern dispute concerns the legal status of Head Harbour Passage. Legal scholarship notes differing Canadian and United States interpretations as to whether the passage constitutes internal waters or an international strait subject to rights of passage under international law.^[12]

From the late eighteenth through the nineteenth century, Passamaquoddy Bay was a significant centre of cross-border smuggling. Modern historians characterise this activity as a structural feature of a transnational borderland economy shaped by weak enforcement, local participation, and shifting trade restrictions.^[13]

Smuggling intensified during the Jeffersonian embargo and the War of 1812, when illicit trade in foodstuffs and manufactured goods moved through the bay between Maine and New Brunswick.

Economic activity in Passamaquoddy Bay has historically been shaped by the bay’s sheltered waters, strong tidal exchange, and proximity to coastal communities in both Canada and the United States.

Passamaquoddy Bay forms part of the outer Bay of Fundy and Gulf of Maine fisheries region, where commercial fishing has targeted groundfish, herring, and shellfish.^[7]

Marine aquaculture has become an important component of the modern economy of Passamaquoddy Bay, particularly on the Canadian side.^[14]

Ports and facilities in communities such as Saint Andrews and Eastport provide services for fishing vessels, aquaculture operations, and visiting craft.^[3]

• Old Sow Whirlpool
• Bay of Fundy
• St. Croix River (Maine–New Brunswick)

• Smith, Joshua M. (2006). Borderland Smuggling: Patriots, Loyalists, and Illicit Trade in the Northeast, 1783–1820. University Press of Florida. ISBN 9780813029863.

• "Passamaquoddy Bay". The Canadian Encyclopedia. Retrieved 25 December 2025.