The Army held a deactivation ceremony at Fort Monroe on Sep. 15, bringing to an end about four centuries of military occupation of the site at Old Point Comfort.

Efforts were made by local and state officials over the last six years to keep Fort Monroe from closing, but the Army vacated the post in September following a decision by the 2005 Base Realignment and Closure Commission (BRAC). The land is due to be transferred to the ownership of the Fort Monroe Authority early next year, although some federally owned parcels do not automatically revert.

Over the last year a groundswell of support for a National Park presence at Fort Monroe has grown in Hampton and the surrounding area. Legislation has been submitted in Congress to create a national park, and Obama has been urged to set up a national monument under the Antiquities Act, a more speedy route to bring a National Park Service presence to Fort Monroe.

A public consultation exercise was held in July that included public meetings and about 2,700 written and online comments sent to the National Park Service, the majority in favor of bringing a national park or a national monument to Fort Monroe.

In August, staffers on Capitol Hill made it clear Obama was looking seriously at proclaiming Fort Monroe's northern sphere – the federally owned parcel referred to as "Dog Beach," a national monument.

However, in the same month the National Park Service told the Fort Monroe Authority it was willing to take on a bigger national park footprint than it (the NPS) had hitherto wanted. The service agreed to take on ownership of the North Beach area, all of Walker Field and a small portion of the moat area in the vicinity of buildings 1, 17 and 50, the buildings it's interested in. A long-term lease is proposed for Casemate 22.

In September, Salazar revealed he was pushing ahead with Fort Monroe's preservation as a national monument by following the Antiquities Act route.

Hampton Mayor Molly Joseph Ward said in a statement Sunday: "We are thrilled and grateful that the President has chosen to use his authority under the Antiquities Act to designate a major portion of Fort Monroe as a National Monument."

Her comments suggest the President is poised to create a larger national monument than envisaged in August when the Dog Beach area was floated as the nucleus of a national monument. While the President can only designate federally owned land a national monument under the Antiquities Act, the footprint of a national monument or park is likely to grow, according to local decision makers.

"A National Monument at Fort Monroe will give the fort the stature it deserves in our nation's history," Ward said. "Very few Americans know the story of the Contraband slaves, and how slavery really ended in the United States. I believe the significance of the President's designation, and the significance of Fort Monroe, will continue to grow in years to come as its story becomes known," Ward said.

Sam Martin of Citizens for a Fort Monroe National Park, a group that has campaigned for years for a national park at Fort Monroe said he was delighted by the news but the President's announcement would only be the first phase because he would only be able to designate the federally owned part of Fort Monroe as a national monument.

However, Martin said it's his understanding that about 324 acres of a 565 acre site would eventually be controlled by the National Park Service. Most of Fort Monroe is due to revert to the Commonwealth of Virginia in early 2012, but the Dog Beach area would remain federally owned. Discussions have been going on behind the scenes between the Army and the National Park Service about land transfers, the Fort Monroe Authority revealed at its September meeting.

The 150th anniversary of the historic contraband decision was celebrated in May. When Monroe's commander, Maj. Gen. Benjamin Butler, refused to return three slaves who came to the fortress in May 1861, effectively classifying them as "contraband" of war, it changed the course of the Civil War and the nation's history. Large numbers of escaped slaves flocked to what became known as "Freedom's Fortress."

Congressman Bobby Scott (D-Newport News) welcomed the expected announcement on Tuesday, as "wonderful news for Fort Monroe, the City of Hampton, the Commonwealth of Virginia, and our nation."

Presidents have created national monuments under the Antiquities Act since 1906 . Theodore Roosevelt, was the first president to use the act. While the designation would not automatically create a national park, it often involves the presence of a National Park Service unit and national monuments, can become national parks at a later date. The 1906 act has been used by previous presidents to protect a host of sites, including the Grand Canyon and the Statue of Liberty.