Traffic was sparse yesterday on winding, tree-shrouded Hunter Mill Road near the Dulles Toll Road. A man stood outside a clapboard house selling Labrador puppies. A church advertised a rummage sale. Cyclists stopped to rest at the Washington & Old Dominion trail's bike path crossing and soak up the autumn sun.

But a few miles away, in the James Madison High School cafeteria, a battle was brewing over the area along this stretch of roadway, which links Reston, Vienna and Oakton. With the help of a private consultant, Fairfax County officials held a public meeting to ask residents how they view the future of their community.

Many residents are worried that the Fairfax County Board of Supervisors will change the comprehensive plan to allow denser development in the Hunter Mill area, which is a few miles from a planned Metro station at Wiehle Avenue in Reston. The Hunter Mill Road dispute is part of a broader discussion along the corridor between Tysons Corner and Herndon about how much development the county should allow if Metro is extended to Dulles International Airport.

At issue is a 309-acre area that is mostly residential or undeveloped. Two developers, WCI/Renaissance and K. Hovnanian, have proposed changing the zoning to allow construction of townhouses and commercial strips. Current zoning allows for houses on two- to five-acre lots, or about 250 houses; the proposed changes could allow up to eight residences per acre, or nearly 1,800 homes.

Many residents voiced strong opposition yesterday to changing the comprehensive plan, which has guided rezoning for two decades. They said denser development could threaten the area's historical character and open spaces, add to congested rush-hour traffic and school crowding, and break down the sense of community.

"Most of us live here because we don't want a super-high-developed dense area," said Judy Naiman, who has lived on Hunter Mill Road for 19 years. "The schools can't handle it. The roads can't handle it."

Tempers flared when Supervisor Catherine M. Hudgins (D-Hunter Mill) told the 250 people who attended that she was "surprised and disappointed" that there was "anger and anxiety about this rather than excitement" over an opportunity to sketch their vision of the future. Hudgins has not taken a position on the proposed rezoning.

A man interrupted Hudgins to ask whether "those of us that you have just slammed" would have an opportunity to give their side.

The Board of Supervisors assembled a citizens task force in June to consider changes to the comprehensive plan and make recommendations to the Planning Commission before the commission, followed by the supervisors, acts on the developers' requests. This is not the first time developers have sought such changes; in the past 15 years, task forces have rejected proposals to increase the density.

County officials and task force members stressed that yesterday's discussion was not about the merits of a particular proposal. Instead, it was about three hypothetical scenarios under which varying degrees of density might affect the community, they said.

Some residents said that whether or not the board changes the comprehensive plan, density increases are inevitable. Jack Wilbern, an architect and member of the task force, said Hunter Mill is one of many areas where such questions will arise as more people and businesses move in.

"In my opinion, this is going to be countywide," he said. "There are going to be changes in this county, and if you say the response should be that . . . we should just stop all job growth in Fairfax County, I don't think that in a democracy we're able to do that."

Breaking up into smaller discussion groups, some residents complained that they were being rushed to discuss proposals about which they had limited information. "Nobody has really seen this whole elephant," said Reza Sadeghi of Reston. "Everyone has seen either the trunk or the foot or the ear, but no one has an idea of what this elephant looks like."

Beverly Quinn and Frank A. de la Fe, the Hunter Mill District planning commissioner, at a meeting yesterday in which residents were asked to offer a vision for the area's future.