The St. Lawrence Reservation (originally known as the State Reservation on the St. Lawrence) was a former protected area established by the state of New York in the Thousand Islands region along the St. Lawrence River in the late 19th century. The reservation's parks were some of the earliest lands purchased by New York State for the purposes of recreation and land preservation.
Initially intended to become part of an international park with islands protected by Canada, properties acquired by New York for the reservation are today managed as independent state parks by the New York State Office of Parks, Recreation and Historic Preservation. Islands that comprised the Canadian portion of the never-realized international park are today part of the Thousand Islands National Park.
During the latter half of the 19th century, the Thousand Islands region increasingly became the focus of outdoor recreation, tourism, and private development. The New York side of the St. Lawrence River in particular became host to a number of lavish private estates built by wealthy newcomers to the region, to the exclusion of recreational visitors; in addition, river anglers grew frustrated with the impacts of illegal fishing and the lack of enforcement of game laws. In response to what they viewed as the spoiling of a formerly open and abundant recreational resource, some of the region's residents and sportsmen began to recognize the need for protection of lands and waters on both sides of the river's international border.
Among the principle proponents of an international park in the Thousand Islands was the Anglers' Association of the St. Lawrence River, who were concerned with protecting the river's fishing resources from commercial exploitation. The association included prominent landowners from both the American and Canadian sides of the river, and during the 1880s they began to lobby both governments to establish consistent regulations and set aside public lands for recreational purposes.