WASHINGTON (AP) — Part of Harriet Tubman's underground railroad in Maryland that helped move slaves to freedom will become a national monument under plans from the Obama administration.

The White House plans to designate new national monuments in Maryland, Delaware and three other states, bringing the historic sites into the National Park Service system.

The Arlington, Va.-based Conservation Fund donated a property on Maryland's Eastern Shore to the National Park Service to help tell Tubman's story of the underground railroad. Tubman escaped slavery at age 27 but returned to Dorchester and Caroline counties to help slaves escape to the North.

In Delaware, Obama will designate the First State National Monument. It will include the Woodlawn Trustees property near Wilmington, the Old New Castle Courthouse, the New Castle Green and the Dover Green.