Besides Port-Cartier itself, the communities of Rivière-Pentecôte (49°47′N 67°10′W / 49.783°N 67.167°W / 49.783; -67.167),[4] Pointe-aux-Anglais (49°40′38″N 67°10′05″W / 49.67722°N 67.16806°W / 49.67722; -67.16806),[5] Baie-des-Homards (49°49′58″N 67°06′41″W / 49.83278°N 67.11139°W / 49.83278; -67.11139),[6] and Grand-Ruisseau (49°44′03″N 67°10′26″W / 49.73417°N 67.17389°W / 49.73417; -67.17389)[7] are also within its municipal boundaries, all located along Quebec Route 138.

In 1915, Colonel Robert R. McCormick, owner of the Chicago Tribune, visited the Rochers River area to evaluate its forest potential.

[3] Mother tongue (2021):[3] The Correctional Service of Canada operates the Port-Cartier Institution, a maximum security prison, about two kilometres to the north.

Port-Cartier Institution is known for its focus on education and vocational training, with a wide range of courses available to help inmates develop new skills and prepare for successful reentry into the workforce upon release.

[17] Notable inmates have included convicted murderers Paul Bernardo, Russell Williams, Michael Rafferty, Mohammed Shafia, Robert Pickton, Luka Magnotta, and Guy Turcotte.