Seaside Park, aka Seaside, was a cannery town on the South Coast of British Columbia, Canada, located near Langdale and Port Mellon on the west, mainland side of Thornbrough Channel, a side-channel of Howe Sound separating Gambier Island from the mainland Sunshine Coast. Another cannery town nearby was Longview, just to the north along the same coastline.
See also List of canneries in British Columbia
References BCGNIS listing "Seaside Park" (locality) Time Traveling - Coastal Canneries of B.C., 1870 website