Imagine a Wal-Mart, Costco Wholesale and Super Target all operating at the same intersection of a small, suburban American town.

Welcome to big-box heaven. Welcome to Leesburg.

"One, two, three -- ohhhhhh," Leesburg Mayor Kristen C. Umstattd said with a broad smile, cutting a ribbon to open a 174,000-square-foot Super Target, the first in the Washington region.

Super Target's debut July 20 was followed by the opening yesterday of a 136,000-square-foot Costco -- both in the same shopping center at the Route 15 Bypass and Edwards Ferry Road.

The Wal-Mart? That's across the street. The 97,000-square-foot discount store has been there since 1993.

"And know something? The Wal-Mart, Costco and Super Target will all do well, working side by side," said Howard Davidowitz, chairman of Davidowitz & Associates, a New York-based retail consulting and investment banking firm. "They're all great companies, and they . . . have different missions."

The two new big-box retailers are betting there are enough consumers in Loudoun and surrounding counties to keep their cash registers full. Costco and Super Target will share the Battlefield Shopping Center with an existing Kohl's department store.

"There's been a demand for a Costco in the Leesburg area for a long time," said Jerry Anderson, a Costco marketing executive. "We have a Costco in Sterling and another one in Winchester. We just felt that putting one sort of in the middle would augment our position in the marketplace."

Costco, Super Target and Wal-Mart will coexist nicely because there's little overlap in their products, and the stores appeal to different income groups, Davidowitz said. The Costco and Super Target have supermarkets; the Wal-Mart in Leesburg does not.

"The shopper at the Super Target and Costco is more affluent than the Wal-Mart shopper," he said. "The Wal-Mart shopper also tends to be a little older."

Costco requires a $45 annual membership but generally has lower prices than Wal-Mart and Super Target, Davidowitz said.

"Costco is not a store for everyday shopping because it sells large packs -- paper, meat, you name it," he said. "Costco also has the lowest profit margin -- about 12 percent -- compared with more than 20 percent for Wal-Mart and Target. But Costco has a smaller assortment of products to sell.

"If you buy toilet tissue at Costco, it may come only in a monster size -- so big that you may not be able to fit it in your closet," Davidowitz added. "But if you are a surgeon who buys wines and gives parties all the time, Costco is the best place to go."

Super Targets, unlike regular Targets, have full-service supermarkets. The Super Target in Leesburg also has a Starbucks just left of the entrance and a Pizza Hut Express to the right.

"Super Target has the same mission as Wal-Mart, except for a more upscale consumer," Davidowitz said. "The merchandise -- mainly, the apparel -- is much more attractive at Super Target. But Wal-Mart will offer the most products that people will buy every day, such as beauty aids, T-shirts, jeans and back-to-school things."

At the ribbon-cutting ceremony, Umstattd said the opening of the Costco and Super Target, side by side, underlines the growth that Leesburg and Loudoun County have experienced in recent years.

When Umstattd came to Leesburg in 1987, she said, "I don't think we could have supported these stores. I'm not certain Loudoun County could have, either."

The county's population grew from an estimated 169,599 in April 2000 to 221,746 in July 2003, according to U.S. Census Bureau data. The 30.7 percent jump made Loudoun the fastest-growing county, by percentage, in the United States.

The new superstores will attract shoppers from outside Loudoun, just as Leesburg's outlet mall has, Umstattd predicted.

"Leesburg is, for better or worse, a center for commuters, both from West Virginia and Winchester and from Maryland," she said. "And I expect we'll get a lot of revenue from these folks coming through."

Helen Sommers of Leesburg shops at Super Target, which, along with Costco, has a supermarket.Matt Thomas manages the Super Target that opened July 20 across the street from a Wal-Mart. A Costco rose next to Super Target.Rebecca Orcutt of Leesburg, at Super Target.