How many national parks does Massachusetts have?

Adams National Historical Park

Longfellow National Historic Site

Appalachian National Scenic Trail

Lowell National Historical Park

Blackstone River Valley National Heritage Corridor

Minute Man National Historical Park

Boston African American National Historic Site

New Bedford Whaling National Historical Park

Boston Harbor Islands National Park

Quinebaug and Shetucket Rivers Valley National Heritage Corridor

Boston National Historical Park

Salem Maritime National Historic Site

Cape Cod National Seashore

Saugus Iron Works National Historic Site

Essex National Heritage Area

Springfield Armory National Historic Site

Frederick Law Olmsted National Historic Site

Sudbury, Assabet, and Concord Wild and Scenic Rivers

John F. Kennedy National Historic Site

Westfield Wild and Scenic River