The Bay is approximately 200 miles (320 km) long from its northern headwaters in the Susquehanna River to its outlet in the Atlantic Ocean. It is 2. 8 miles (4. 5 km) wide at its narrowest (between Kent County's Plum Point near Newtown and the Harford County shore near Romney Creek) and 30 miles (48 km) at its widest (just south of the mouth of the Potomac River). Total shoreline including tributaries is 11,684 miles (18,804 km), circumnavigating a surface area of 4,479 square miles (11,601 km2). Average depth is 21 feet (6. 4 m), reaching a maximum of 174 feet (53 m). The Bay is spanned twice, in Maryland by the Chesapeake Bay Bridge from Sandy Point (near Annapolis) to Kent Island and in Virginia by the Chesapeake Bay Bridge-Tunnel connecting Virginia Beach to Cape Charles. Known for both its beauty and bounty, the Bay has become "emptier", with fewer crabs, oysters and watermen in past years. Recent restoration efforts begun in the 1990s have been ongoing and show potential for growth of the native oyster population. The health of the Chesapeake Bay improved in 2015, marking three years of gains over the past four years, according to a new report by the University of Maryland.