For over 50 years, Skaggs Island was a secretive, secure, and self-contained naval base, engaged in a number of communications and intelligence gathering functions for the Navy and other federal intelligence organizations. Direction-finding high-frequency antennas, for example, could aid in locating distant sources of communications by intercepting signals bouncing off the ionosphere. The 3,310 acre site was purchased by the Navy in 1941, and closed in 1993, but the antennas continued to be used for some time after that. A staff of up to 400 people were stationed here, and most of the buildings are residential and recreational buildings, including rows of single story homes, a theater, mess hall, recreation center, chapel, bachelor's quarters, and administrative buildings, all of which are now abandoned and in a state of disrepair. Beyond the main base and an unrelated aviation beacon (a VOR antenna), the only other structures of any size on the base are two block houses that contained transmitting and computer equipment. They are now abandoned and stripped of their contents. The walls of these buildings have been perforated by Navy SEALs practicing forced entry methods, using explosives that create round entry holes. In 2010, 3,300 acres of the island were purchased by the U.S. Fish and Wildlife Service, with the intention of adding it to the San Pablo Bay National Wildlife Refuge. In 2013, the Natural Resources Conversation Service purchased the remaining 1,092 acres, which were then transferred to the U.S. Fish and Wildlife Service, who plan on restoring most of the island to wetlands and tidal protection zones.