Annie Snyder's home sits on a hill, where a view of the rolling countryside sends the mind wandering into the past. Union and Confederate troops marched these pastures north of Manassas, clashing in two major battles of the Civil War.

The latest conflict to engulf this land along the frontier of suburban Washington starts on this hill every day at 4 a.m. Snyder, a 66-year-old former marine, marches into her upstairs study, sits down at a computer and goes to battle against John T. (Til) Hazel, who plans to build a Tysons Corner-size shopping mall next to the Manassas National Battlefield Park.

The news came two weeks ago when the Hazel/Peterson Cos., Northern Virginia's most prominent developer, said it was joining with the Edward J. DeBartolo Corp., the nation's largest builder of shopping centers, to build a 1.2 million-square-foot mall on a prime piece of Prince William County land.

The development, known as William Center, would sit where Confederate Gen. Robert E. Lee had his headquarters during the Battle of Second Manassas, a site adjacent to the national park.

"They dropped a bomb on this county," Snyder said of the proposal, which drew her out of retirement as Prince William's most prominent civic activist and placed her at the head of an angry coalition of hundreds of historic preservationists and area residents organizing to defeat the proposal. Two members of Congress have joined the fracas.

Prince William's elected officials on the Board of County Supervisors, by contrast, have been nearly unanimous in praising the project. They say it already has the zoning it needs, and that nothing can be done to stop it.

Opponents have promised a lawsuit and are considering congressional action to prevent the mall from being built.

The clash has transfixed Prince William, where soaring growth recently pushed the once-rural county's population over 200,000, making it the second-largest locality in Northern Virginia. The confrontation offers a matchup of some of the most formidable forces in local politics.

On one side is Hazel, one of the region's wealthiest citizens, and a lawyer and developer who has left an imprint on the landscape so deep that some have described him as the closest thing Northern Virginia has had to L'Enfant.

With his Virginia drawl, hefty frame and distinctive crew cut, Hazel seems the epitome of an old-time country lawyer. Yet his developments are cornerstones of modern-day Northern Virginia: Fairfax County's giant Burke Centre and Franklin Farms communities, as well as the celebrated Fair Lakes complex eight miles east of the Manassas battlefield on I-66.

Hazel wins praise in the development community as someone who has an intuitive sense of the possibilities of open land, buttressed by the conviction that his work is making the region a better place to live.

The DeBartolos are also well-known. The Ohio family has built dozens of shopping centers around the country, and owns pro football's San Francisco 49ers and the Pittsburgh Penguins hockey team.

The developer and his associates are joined by county officials and many residents eager for the money and prestige a first-rate shopping center would bring to Prince William.

The mall, they say, would produce about $180 million in net revenue during the next 20 years in a county pitching and heaving to meet the burdensome costs of residential growth. The unrelenting tide of new residents -- most of them living in the county's eastern end, miles from the battlefield site -- has clogged Prince William's roads and classrooms and strained virtually every other aspect of government services.

The William Center tract "is the key to quality economic development" in western Prince William, said Hazel, who argues that the real threat to the area's landscape is the "nebulous, ad hoc" growth that has sprung up elsewhere around the battlefield.

Confronting this array of developers and government officials are Snyder and her allies. They argue that the need for tax dollars must yield to the imperative of preserving hallowed and historic ground.

Snyder and her coalition eagerly claim the role of underdogs battling rich and powerful interests, but that may be a bit misleading.

Snyder, a conservative Republican who can be cantankerous or charming to fit the circumstances, has been leading political crusades in Prince William since the early 1950s, when she moved to a 188-acre farm near the battlefield. More often than not she has won.

In 1976 she led the campaign that forced the Marriott Corp. to walk away from its proposal to build an amusement park on the property where Hazel/Peterson now wants the mall.

The wall of her study is covered with cabinets storing files from countless fights to stop proposed road improvements, bond issues and developments. (Old press clippings are divided into "biased" and "fair.") She often breaks into tears when talking about her efforts to save the county's open spaces.

Nonetheless, Snyder, a diabetic, had declared that she was through crusading, in part because she ignored her health when in the middle of a political scrap. Her husband and six children were afraid the civic controversies would lead to her grave.

Hazel/Peterson's project lured her back to the fray.

Snyder and the other mall opponents have enlisted the support of at least two representatives in their effort to stop the project. Democrats Michael A. Andrews of Texas and Robert J. Mrazek of New York said they became involved because of their interest in history.

Gen. Lee established a command post on what is now the William Center site during the bloody Battle of Second Manassas, which raged on Aug. 29 and 30 in 1862, 13 months after the war's first major land engagement during the Battle of First Manassas. (In states north of the Mason-Dixon line, the conflicts are known as the Battles of Bull Run.) At Second Manassas, Confederate forces routed the Union in a victory that allowed Lee to cross into Maryland to launch his Antietam campaign.

The battle over Hazel/Peterson's project -- a fight over the future of Prince William -- is colored by longstanding tensions in this county, which has kept one foot in rural Virginia even as more than two decades of explosive growth has planted the other solidly in metropolitan Washington.

Some mall supporters boast that the development will sever the final link to Prince William's backwater past, when the county was an undesirable cousin to its more affluent neighbors. When Hazel/Peterson announced plans for the shopping center, Supervisor Robert L. Cole (D-Gainesville) hailed the news that Prince William would "no longer stand in the shadow of Fairfax County."

"The growth is long overdue," said Rene Dosh, who moved to western Prince William in 1981, adding that the mall should boost the value of her family's home. It's about time, Dosh said, that county residents had tonier alternatives to the discount department stores that line Prince William's main drags.

Yet on the gently sloping hills of western Prince William are people who relish the notion of living in "a backwater." These people, both natives and recent refugees from urban areas, see the mall as an assault not just on historic land, but also on a way of life. Where a shopping mall goes, they argue, sure to follow are traffic, crime and visual blight.

Judy Simpson said she and her husband left Fairfax County for Prince William 12 years ago because "we wanted to move out to the boondocks." Since then, she said, it seems she has "done nothing but fight" intrusions on that rural atmosphere.

The controversy over the shopping mall is complicated by the history of the William Center tract. The property, whose location near the confluence of three major highways -- I-66 and Rtes. 234 and 29 -- has long made it one of Prince William's crown jewels for economic development, was rezoned by the Board of County Supervisors in November 1986.

At the time, Hazel/Peterson advertised the project as a "mixed-use" development with an emphasis on corporate offices, similar to its Fair Lakes complex. There would be about 560 homes and a neighborhood shopping center.

Snyder and many people now concerned about the mall supported the rezoning, albeit reluctantly. If the property had to be developed, an office park was probably the least offensive alternative, they reasoned. Hazel/Peterson's reputation as a builder of quality developments was reassuring, as was the firm's willingness to leave buffer zones between the property and the battlefield park.

Only recently, Hazel has said, did the firm's plans change. Efforts to attract major corporate tenants had lagged, and DeBartolo's unexpected interest in building a mall sounded attractive, Hazel said. Although William Center will remain a mixed-use complex, the shopping center will now be the hub of the project and serve as a catalyst for other development at the site, according to the developers.

Although the thrust of the project has changed, Prince William County Attorney John H. Foote has told the supervisors that the 1986 rezoning was "very general" and that the developers do not need additional approval from the county board to build the mall.

Hazel/Peterson's change in course and the county's acquiescence have left the mall's opponents indignant. "We feel deceived, cheated and defrauded by Hazel/Peterson and betrayed by our county government," Snyder said.

A recent meeting of mall opponents drew an irritable crowd of more than 220 to an auditorium at the national park. Among the groups that have signed on to block the mall are the Civil War Roundtable, the United Daughters of the Confederacy and the National Parks and Conservation Association.

National Park Service Director William Penn Mott Jr. has written board of supervisors Chairman Kathleen K. Seefeldt (D-Occoquan), complaining that the shopping mall project "does not even resemble . . . the good-faith agreements" the Park Service reached with the county regarding development around the battlefield.

Snyder said opponents hope to raise $200,000 to battle the shopping center in court, arguing that the William Center rezoning is inconsistent with the project now proposed.

Andrews and Mrazek said they may be able to bring congressional pressure to bear on Hazel/Peterson through the Department of Transportation, which would have to approve any new interchange on I-66. Without an interchange, a mall on the William Center site would likely be unfeasible.

"I am ready to take the first available vehicle" to stop the mall, said Mrazek, a member of the House Appropriations transportation subcommittee. His first preference, Mrazek said, would be to have the federal government purchase the tract and incorporate it into the national park.

Hazel, who said he is a student of the Civil War, said the mall would be no more intrusive on the national park than an office park, and arguably less so. He called it "a terrible commentary on society" that members of Congress and others he considers ill-informed about the particulars of the development would try to stop it.

"When you get involved in these emotional things, people don't want to know the facts," he said.

The mall opponents don't deny that they are buoyed by strong emotion. Said Betty Rankin, a leader in the fight: "This isn't a battle, this is a war."