The $30 million City Museum of Washington is on track to open this spring in the old Carnegie Library across from the new convention center in Mount Vernon Square, officials said.

Barbara Franco, director of the Historical Society of D.C., which will run the 60,000-square-foot museum, said she expects construction to be completed by March. The museum is slated to open May 15.

In a town overflowing with museums, Franco said, the City Museum of Washington is unique because it will be the only one devoted to the city itself -- its history, neighborhoods and people.

Plans include a first floor featuring a giant floor map, a changing multimedia show in the 150-seat theater and community galleries focusing on neighborhoods, beginning with Chinatown and Mount Vernon Square.

The second floor would house two more galleries and a public reading room and library.

The basement would feature an archaeology lab, with classrooms and workshops.

The historical society plans to use the third floor as office space, moving out of the Heurich House, a lavish but cramped 18th-century brownstone near Dupont Circle that is open to the public for tours. The society's move drew some criticism from residents, who expressed concern that the house would not be preserved.

As of mid-December, Heurich House was still on the market, listed at $7.2 million. It was originally priced at $9.9 million.

Franco said last week that there has been "a lot of interest" in the house and that a formal bid was expected soon.

"Our priorities are to find someone who will be a good steward of the house . . . [and] that it continue to have some kind of public accessibility," she said.

The society has raised slightly more than $15 million in its $20 million capital campaign, which is to last another year.

-- Ylan Q. Mui

The old Carnegie Library in Mount Vernon Square is being converted to house the City Museum of Washington. The museum is dedicated to local history.