1958 Map of Thousand Island Park

Evidence of early 20th-century development is visible in the cluster of island settlements like Grenell and the riverfront hamlet of Fishers Landing. Large tracts of preserved land are already established, including Wellesley Island State Park and Canoe Point and Picnic Point State Park. Across the water in Ontario, the Canadian National rail line runs near Wilstead, while the Thousand Islands Parkway follows the northern shoreline, marking the region's transition into a premier mid-century vacation destination.