Days after the federal government abandoned plans to house immigrant children in a Baltimore office building, the Obama administration has begun to explore other sites in Maryland, including one in Prince George's County, documents obtained by The Baltimore Sun show.

On Tuesday, the U.S. Department of Health and Human Services evaluated a former residential drug treatment facility in Upper Marlboro with a storied past as the administration struggles to find enough shelter space to contain the recent surge in unaccompanied children crossing the nation's Southwest border.

The agency has also considered a boarding school in Montgomery County, but has dropped that idea.

The rapid pace with which the health agency is evaluating sites in Maryland underscores the extent to which the administration is scrambling to address an influx that White House officials have described as an "urgent humanitarian situation."

About 9,500 children were caught at the Southwest border in May, a 300 percent increase over the same period last year. Most are coming from Honduras, Guatemala or El Salvador — Central American countries torn by gang violence.

It is unclear whether more sites are under review for use as shelters in Maryland than in other states.

A proposal to place hundreds of children at the vacant Metro West complex on Baltimore's west side met with stiff opposition last week from Sens. Barbara A. Mikulski and Ben Cardin. The plan was abandoned days after it was first reported by The Baltimore Sun.

There has been less resistance from elected leaders to the new sites that have surfaced, but officials cautioned that the Prince George's proposal, for instance, is still in an early stage of evaluation.

Mikulski said her "first concern is for the health and safety of these children who have made a perilous journey to escape violence at home."

"Federal agencies must work closely with local communities and nonprofits to select sites that meet the unique needs of these vulnerable children," the Maryland Democrat said. "We must be careful to select sites that are kid-friendly. Being empty and available cannot be the only criteria we use."

The Department of Health and Human Services is charged with caring for the children until their deportation proceedings begin.

Documents show that officials are considering a 68-acre site on Melwood Road in Upper Marlboro to house some of the children. State records show that the property, once occupied by the Washington-based German Orphan Home, is now owned by an addiction-recovery organization based in Silver Spring called Second Genesis.

A message on the group's website, posted in February, says "state and local government budget issues" had forced it to suspend all operations. Attempts to reach members of the group's board by phone and email were unsuccessful.

The German Orphan Home moved to the Upper Marlboro site from Washington in the 1960s and continued to house children there until 1979.

The site then became a shelter for battered women. But that was closed in 1980 amid allegations of misused funds, The Washington Post reported at the time.

State property records show the German Orphan Home sold the property to SG Housing Corp. in 2001 for $1.6 million. SG Housing lists the same Silver Spring address as Second Genesis.

A spokesman for Prince George's County Executive Rushern L. Baker III, said the county had not been contacted by the federal government about the proposal and could not comment.

Rep. Donna F. Edwards, whose district includes the facility, also declined to comment.

Health and Human Services has not confirmed or commented on sites it might be considering.

The department is reviewing hundreds of buildings across the country as potential shelters. Officials have opened space for the children at Lackland Air Force Base in Texas and Fort Sill in Oklahoma.