Harriet Tubman National Historical Park and Harriet Tubman Underground Railroad National Historical Park Act - Establishes in the City of Auburn, New York, the Harriet Tubman National Historical Park as a unit of the National Park System. Establishes in Caroline, Dorchester, and Talbot Counties, Maryland, the Harriet Tubman Underground Railroad National Historical Park as a unit of the National Park System. Authorizes the Secretary of the Interior to provide grant funding and enter into cooperative agreements with certain entities for the historic preservation, rehabilitation, interpretation, and maintenance of such historical parks. Requires the Secretary to complete a general management plan for them.