This article argues that the red-ocher paintings (pictographs) in Coast Salish Tsleil-Waututh territory in Indian Arm, British Columbia, were made around the time of contact in specific response to demographic collapse caused by smallpox. Tsleil-Waututh people selected fifteen distinctive geological features along the shoreline of Indian Arm for marking. It is suggested that these locations were highly significant places to past Tsleil-Waututh people because they were physical embodiments of oral traditions (sxwoxwyiam) and associated with underwater-dwelling supernatural creatures (stl’aleqem). Relying on local oral traditions, regional archaeology, and local ethnographies, the article argues that these specific locations had very ancient roots in Tsleil-Waututh history but were marked in the early contact period with red paint by Tsleil-Waututh ritualists (shxwla:m, “Indian Doctor”). They did this to connect with supernatural powers in these locations, to preserve oral histories associated with them, and thus to contribute to the demographic revitalization of the Tsleil-Waututh people. The article contends that Tsleil-Waututh rock painting is not an essentialized cultural practice but a historically contingent one—a reflection of specific events.