The Pinellas National Wildlife Refuge is part of the United StatesNational Wildlife Refuge (NWR) System, located offshore from mainland St. Petersburg, Florida, and only accessible by boat. The 394-acre (1.59 km2) refuge was established in 1951, to act as a breeding ground for colonial bird species. Islands within the refuge include Indian, Tarpon, Mule, and Jackass Keys, and all are within the St. Petersburg city limits.