The Saint John River is a 673-kilometre-long (418 mi) river flowing within the Dawnland region from headwaters in the Notre Dame Mountains near the Maine-Quebec border through western New Brunswick to the northwest shore of the Bay of Fundy. Eastern Canada's longest river, its drainage basin is one of the largest on the east coast at about 55,000 square kilometres (21,000 sq mi). This “River of the Good Wave” and its tributary drainage basin formed the territorial countries of the Wolastoqiyik and Passamaquoddy First Nations prior to European colonization, and it remains a cultural centre of the Wabanaki Confederacy to this day.

Maliseet-Passamaquoddy is an endangered Algonquian language spoken by the Maliseet and Passamaquoddy peoples along both sides of the border between Maine in the United States and New Brunswick, Canada. The language consists of two major dialects: Maliseet, which is mainly spoken in the Saint John River Valley in New Brunswick; and Passamaquoddy, spoken mostly in the St. Croix River Valley of eastern Maine. However, the two dialects differ only slightly, mainly in their phonology. The indigenous people widely spoke Maliseet-Passamaquoddy in these areas until around the post-World War II era when changes in the education system and increased marriage outside of the speech community caused a large decrease in the number of children who learned or regularly used the language. As a result, in both Canada and the U.S. today, there are only 600 speakers of both dialects, and most speakers are older adults. Although the majority of younger people cannot speak the language, there is growing interest in teaching the language in community classes and in some schools.