Here's the assignment: Convince tourists that there's more to Washington than the District, with its grand monuments, museums and White House.

This is the task the Washington suburbs have taken on as they invest more in tourism as an economic development tool, trying to persuade day-trippers and overnight travelers to see the value of spending their time and money in Virginia and Maryland.

More than 17 million tourists visit the District every year, spending about $11 billion, according to the Washington, D.C., Convention and Tourism Corp., and once they have seen the Capitol Dome and the museums on the Mall, some have always gone on to well-established destinations such as George Washington's home at Mount Vernon and the Civil War battlefield at Manassas.

Hoping to expand on that base, suburban communities are not only building more attractions, they are also spending more money to market those they already have.

"It's not enough to have attractions," said Alisa Bailey, president and chief executive officer of the Virginia Tourism Corp. "That's important. But you've got to have the money to market them. Marketing is the lifeblood of tourism."

Prince William, the county that would have been the home of Disney and Legoland theme parks until plans were dropped in the mid-1990s because of local opposition, has four especially large projects in progress: a $56 million performing arts center, a $50 million luxury hotel and conference center, an $80 million Marine Corps museum and a $120 million science center.

Such efforts come as the region recovers from the negative effects on tourism of the Sept. 11, 2001, attacks. In Northern Virginia, Mount Vernon attendance was down to 918,328 last year, for example, from 1 million in 2000 and 2001.

"I think attractions in general are really still struggling," said Stephanie Brown, Mount Vernon's associate director for public affairs. She expects 2005 attendance figures to exceed last year's as Mount Vernon plans an $85 million expansion that it expects to open at the end of next year.

Spending associated with tourism has been slowly rising. The economic impact of tourism in Virginia was estimated at $14.5 billion in 2000 and at $15.2 billion in 2003; in Maryland, comparable figures rose from $8.3 billion to $9.3 billion, according to the Virginia Tourism Corp. and the Maryland Office of Tourism.

Convention bureaus in Northern Virginia received $900,000 in federal money in 2003 to pay for more marketing.

"Tourism, if it's properly promoted and managed, can be a source of relief for taxpayers," said C. Arnie Quirion, president and chief executive officer of the year-old Visit Fairfax office, which is financed by a local hotel tax. "In the tourism industry, these folks are kind enough to come into our area and spend money and go home and be replaced with people who want to do the same thing."

Not everyone is so optimistic. Some planners contend that tourism tends to create low-paying service jobs, rather than good-paying jobs that support families and strengthen economies.

Matthew Chase, executive director of the Washington-based National Association of Development Organizations, said many communities across the country thought tourism would sustain them when their manufacturing and agricultural jobs began to disappear.

"It basically started out of survival and opportunity," he said. But, he noted, tourism can be a cyclical business. "You can't survive or thrive on tourism alone." His organization represents 320 regional groups, most of which have a tourism strategy.

A Napa Valley with its scenery and vineyards obviously can lure tourists from San Francisco, said Jeffrey A. Finkle, president and chief executive officer of the District-based International Economic Development Council, but not every scenic landscape is a Napa Valley.

"If you're Aspen, Colorado, is there any question?" Finkel said. "If you're Prince George's County, Maryland you're going to work differently at your tourism strategy."

As it began to develop a marketing plan, the new Visit Fairfax agency paid for a study to find out what it was up against. It found that the District attracts 67.7 percent of business spending and 58 percent of the money spent by leisure travelers in the region. Travelers did not have a clear idea of Fairfax's identity, considering the county "far flung," and are confused about where attractions are and how to get to them.

Fairfax recently launched a promotion called Passport to Adventure, offering visitors a chance to win prizes this summer if they visit three sites in the county and have "passports" stamped.

Convention and tourism bureaus in Fairfax, Loudoun and Prince William counties and the cities of Fairfax and Alexandria started a campaign called Pursuit of Happiness, promoting the region with billboards, brochures and a 90-second video shown on United Airlines flights out of Washington Dulles International Airport.

Jo Anne Mitchell, president and chief executive of the Alexandria Convention and Visitors Bureau and spokeswoman for the Northern Virginia Visitors Consortium, said: "I think that we all understand that when people come to our area they don't know when they're crossing these tax boundaries. They just care about being in the region and seeing the things they want to see."

By one measure, hotel occupancy, the suburbs are drawing out-of-towners. In the first six months of the year, occupancy in Fairfax County hotels rose to 76.5 percent from 74.7 percent in the comparable period last year, according to Smith Travel Research of Hendersonville, Tenn. The county has the most hotel rooms in the area outside of the District and its occupancy rate has risen every year since 2001, although it remains lower than the 77.1 percent of 2000.

The suburbs offer cheaper rooms than in the District, where the average room rate was $186.21 in the first six months of 2005, compared with as little as $74.88 in Prince William County, Smith Travel Research said.

Other measures are less clear. An offshoot of the Smithsonian National Air and Space Museum, the $311 million Steven F. Udvar-Hazy Center, opened near Dulles airport at the end of 2003. It drew 1.6 million visitors its first year. That made it the most-visited museum in the state, according to the museum, though it is still trying to reach its goal of 3 million a year.

While tourists who get there ooh-and-ahh at the space shuttle Enterprise and the Enola Gay artifacts on display, some are put off by the $12 parking fee, though the museum itself, like other Smithsonian museums, has no admission fee.

"I can't believe people do come here just because you have to pay so much to park," said Fran Nelson, an Arlington resident who brought a friend from Arkansas to the museum.

"It surprises me why they put it out here," said Nelson, who considered the magnitude of the traffic on a Friday afternoon before she drove to the museum, 27 miles from the main Air and Space Museum on the Mall.

The organizers of the projects in Prince William chose the county for the same reasons many residents did -- more land available at more affordable prices than in the District or closer-in communities. And local and state officials were eager to encourage them with financial incentives.

County officials donated land in Quantico for the National Museum of the Marine Corps and Heritage Center on a 135-acre campus. The interactive museum will offer visitors a boot-camp experience, with recorded instructors barking at tourists to stand motionless on the yellow footprints painted on the ground, just as Marine Corps recruits must do when they arrive for their first day of training. The museum is expected to open in 2006 and attract more than 300,000 visitors a year.

For the 200,000-square-foot Belmont Bay Science Center on the banks of the Occoquan River in Woodbridge, voters approved $5 million for construction, the federal government awarded $589,000 and a local developer donated the land. The center, with a freshwater laboratory and classrooms, is expected to attract more than 673,000 visitors and generate $54.8 million for the local economy annually after it opens in 2007, according to a study by Cambridge, Mass.-based ConsultEcon Inc.

Planners count on visits from the rapidly growing and increasingly affluent population of Prince William County, where the Manassas battlefield and the Potomac Mills shopping mall are established tourist destinations.

Washington's suburbs have long had an interest in tourism because the District draws so many visitors.

"We feed off of Washington, D.C., because that is a well-known market," said Dennis M. Castleman, Maryland's assistant secretary for tourism, film and the arts.

Much of Maryland's tourism centers on Baltimore with its Inner Harbor and National Aquarium, and Annapolis with its boat-filled waterways. But the counties close to Washington try to take advantage of their proximity to the District, such as Howard, which advertises Ellicott City's historic main street and special hotel packages, and Prince George's, which promotes itself as a good place for family reunions.

About 2 million people will visit Prince George's County this year and many of the summer visitors are attending family reunions organized primarily by African American residents like Sandy Arnett.

Every year, the Capitol Heights resident plans her family reunion in different areas of the country. This year, the McCory family reunion was held in Maryland and attended by nearly 100 people. Relatives filled 52 rooms in the Greenbelt Marriott hotel and spent their weekend eating at an area buffet-style restaurant, praying and singing during a family church service held in the hotel and sharing birthday cake with their oldest relative, who turned 91.

Raleigh residents Gilbert McCory and his sister Alisha Mills said the highlight of their weekend retreat was the family reunion, but they also enjoyed visiting the Washington Monument and the National World War II Memorial.

"It was beautiful," said McCory, who visited the District before attending the reunion in July.

Other tourists hearing the suburban message say they are satisfied with what they found.

Donna and Richard Beckett, a retired couple on a cross-country trip from their home in San Francisco, noticed advertising for the battlefield in Manassas and decided to visit. They also saw the National Firearms Museum in Fairfax and the Air and Space Museum annex at Dulles.

"It's really good," Donna Beckett said one recent morning, standing on a landscape of rolling hills dotted with Civil War cannons.

The space shuttle Enterprise in its huge hangar is a big draw at the Smithsonian National Air and Space Museum annex near Washington Dulles International Airport.

Attendance at Mount Vernon was down in 2004 from 2001, but the museum expects to rebound this year. An expansion is scheduled to open next year.