It is an economic development prize nearly unparalleled in the Washington region: the chance to pour 11,000 federal employees into a single neighborhood in one stroke.

The planned relocation of FBI headquarters from the crumbling and dated J. Edgar Hoover Building in downtown Washington has sparked a flurry of jockeying from state and local officials eager to lure the G-men to their jurisdictions.

On Tuesday, the General Services Administration announced that it had winnowed the list of possible sites to three finalists, all of them in the suburbs: Greenbelt and Landover in Prince George’s County and Springfield in Fairfax County.

None of the three sites is much to look at now. In Greenbelt, there is a sea of Metro parking lots and a Kiss and Ride; in Landover, a mostly demolished shopping mall; and in Springfield, a government warehouse and a CIA facility so secure that hardly anyone has been inside.

But all three locations offer a rare combination of value to the GSA: the capacity to accommodate a 2.1-million-square-foot campus within 21 / 2 miles of the Capital Beltway and two miles of a Metro station, requirements the federal government made when it initiated the search.

The new headquarters probably will be the largest new federal campus since the CIA moved to Langley, Va., in 1961, accommodating FBI personnel from 20 locations around the region.Top lawmakers and deep-pocketed real estate developers are salivating over the possibilities.

Unlike the CIA headquarters in Langley, the FBI complex — in part because it is pegged for locations near Metro stations — carries the possibility of being able to generate an economic boost that probably would include ancillary housing, shopping possibilities, offices and hotels.

And the final selection of a site later this year is likely to launch a second economic boom downtown when the current headquarters is pegged for demolition and redevelopment.

D.C. officials normally would express regret over losing a major federal agency. But the prime location of the Hoover building, on pricey Pennsylvania Avenue NW, means the city will be able to rid itself of an inefficient building that often is listed among the ugliest in the city, most likely replacing it with a tax-generating project that would include high-priced residential, office or retail space.

“Overall, this is hugely positive,” said D.C. Mayor Vincent C. Gray (D).

Del. Eleanor Holmes Norton (D-D.C.), who historically has fought to keep major agencies in the capital, issued a statement saying she took “considerable comfort in knowing that at last the current FBI headquarters site is now ripe to bring new jobs and revenue to the District of Columbia.”

Pulling off both the relocation of the FBI and the redevelopment of the Hoover building will not be easy. The GSA has proposed paying for the FBI’s new digs by offering real estate developers, in a separate competition, the chance to trade for the Hoover building. Developers will be able to compete to acquire the building regardless of whether they own any of the sites under consideration for the FBI.

Members of Congress also are likely to push the GSA to reduce costs and maximize efficiency for the FBI consolidation, which could hinder or delay the project. Disagreements about the future headquarters of the Department of Homeland Security have badly sidetracked that agency’s long-planned relocation to the former St. Elizabeths hospital in Southeast Washington.

The GSA’s selection of the three sites as finalists triggered renewed competition between the Maryland and Virginia congressional delegations, which historically have worked in concert to promote federal spending in the region but have not been shy about cheerleading to bring specific projects to their own states.

“In terms of where the FBI employees would like to be, access to Metro, access to Quantico, we’re a clear winner,” said Sen. Mark R. Warner (D-Va.), referring to the FBI crime lab in Quantico.

Maryland lawmakers disagreed and sharply disputed suggestions from Warner, Rep. James P. Moran (D-Va.) and other Virginia officials that Greenbelt and Landover were too far away from the homes of FBI workers or other key federal installations.

“Wrong, wrong, wrong, wrong,” said Sen. Benjamin L. Cardin (D-Md.). “Most of the percentage of the workers of the FBI live in Maryland. Check their facts. Secondly, we’re more convenient to the Metro. Check the facts. Third, we have the campus facility and land that they need, and you can get a fully consolidated FBI site. And last — which they forgot to mention, because even they would not challenge this — the cost would be less in Prince George’s County.”

The selection of the Greenbelt site as a finalist was widely expected. The proposed 82-acre site is located at the Greenbelt Metro station. Metro and a private developer have been trying to develop the site for more than a decade.

The other Maryland property being considered is the vacant 88-acre former home of Landover Mall, owned in part by Lerner Enterprises, the real estate firm of Washington Nationals owner Theodore N. Lerner.

In Springfield, the site under consideration includes federally owned land and properties owned or controlled by Boston Properties, one of the biggest real estate developers on the East Coast. One potential problem with the site is that a secure CIA facility remains in operation there, with no plan yet announced to relocate it.

Sen. Barbara A. Mikulski (D-Md.), chairman of the powerful Appropriations Committee, used political terms at an afternoon news conference on Capitol Hill to describe the importance of the decision before the GSA.

Being selected as a finalist, she said, “is like winning the primary. Now, we’re suiting up to win the general [election].”

The decision to include two Prince George’s sites is an indication, Mikulski said, that the federal government finally wants to take advantage of wide swaths of the county that remain underdeveloped compared with the District and other parts of the region.

“For too long, we think, Prince George’s County has been redlined, sidelined, overlooked and undervalued,” she said.

Members of the Maryland congressional delegation and Prince George’s County Executive Rushern L. Baker III (D) previously have made it clear that they prefer the Greenbelt proposal over the one in Landover, and the county has offered a subsidy package for Greenbelt worth $112 million.

But after Tuesday’s announcement, Maryland officials began to embrace the luxury of having two finalists.

“Aren’t we lucky that we get two bites of the apple?” Baker said. He said he had assurances from Maryland Gov. Martin O’Malley (D) that the state would do “everything” to ensure that both sites are prepared to accommodate the FBI.

But Sharon Bulova, chairman of the Fairfax County Board of Supervisors, said in an interview that having just one finalist in her state might be an advantage.

“Virginia is united around this site,” Bulova (D) said. “We have one site that we are working real hard toward. Maryland has several sites, but Fairfax County and Virginia have this site that we are going to be working very hard to secure the FBI.”

Ed O’Keefe and Mary Pat Flaherty contributed to this report.