The Algonkin maintain that their ancestors originally migrated to the upper Saint Lawrence Valley from the east, a tradition they share with the closely related Ojibwe, Ottawa, and Pottawatomie. The timing of this seems to have been sometime around 1400, but when Jacques Cartier made his first visit to the St. Lawrence River in 1534, he found Iroquois-speaking people living along the river between Quebec (Stadacona) and the rapids at Montreal (Hochelaga).
"Algonquian" is not the name of a native tribe or nation; it is a language family, like "Roman" or "Indo-European". There are no "Algonquian Indians". There are dozens of North American Nations that speak Algonquian language all across the United States. The languages and their speakers are as different from each other as French and Spanish and Italian are. Most of the New England tribes spoke Algonquian languages, and many of the "Indian" words common in English today - such as raccoon, succotash, Massachusetts, moccasin, etc. - are from one or another of the Algonquian languages, such as Abenaki, Wampanoag, Nipmuc, Penboscot, Shawnee and Delaware.