"This national monument will tell the story of the essential role my state played in the history of the United States. I couldn't be more proud to call Delaware home," said Vice President Biden.
The drive to turn the property into either a national monument or national park - there is pending legislation for the latter - has had wide support from conservationists, community and civic groups, elected officials, and the Lenni-Lenape tribe.
The Brandywine acres were purchased by the Conservation Fund last year with a $20 million donation from Delaware's Mount Cuba Center, a conservation and horticultural nonprofit associated with the du Pont family. The fund has committed to donating the land to the park service if it becomes a national monument or park.
Sen. Tom Carper (D., Del.), a sponsor of the national park legislation and a longtime supporter of Delaware's having its own national park, thanked the president and said he still wanted to work on national park status.
"Today, not only does the national park system gain an important story about the crucial role the First State played in the founding of our country - a story that will be preserved for generations to come - but our state can now welcome the many economic opportunities that surround a new national monument and can help boost local business and create jobs," Carper said.
The property will be managed by the park service.
"It's fitting that the National Park Service round out its presence in every state by establishing a park in the very first state," said Blaine Phillips, mid-Atlantic regional director for the Conservation Fund.
Contact Rita Giordano at 610-313-8232, firstname.lastname@example.org or on Twitter @ritagiordano.