Dominion Virginia Power is planning to run a high-voltage power line through Gainesville and Haymarket in Prince William County, both to meet anticipated electricity needs in the county and to serve one particular customer, whom the company will not name.

Local opposition is growing in just the two weeks since residents found out about the plan for a 230,000-volt line, which would run for six miles from a north-south line in Gainesville. The line, on 120-foot poles, would run along Interstate 66, cut across a wooded area near Catharpin Road in the Somerset Crossing neighborhood, and then run parallel to the north fork of Broad Run and the Norfolk Southern train tracks behind the Greenhill Crossing neighborhood to an as yet-unbuilt substation in Haymarket.

Residents say the line would cut through protected wetlands, reduce property values of entire neighborhoods and possibly cause health problems. Jim Napoli, president of the Somerset Crossing homeowners association, said a quickly called community meeting last week drew 200 Gainesville residents.

“The community is very upset about the proposal,” Napoli said. “We didn’t sign on for these monstrous towers of 230,000 volts of electricity surging through us.”

Corey A. Stewart, chairman of Prince William’s Board of County Supervisors, said he was baffled by the plan and had not been given a reason by Dominion for the sudden expansion of power to an area near the county’s “rural crescent,” where heavy development is largely prohibited. But the line’s path will not be determined by the supervisors: It will be set by the State Corporation Commission after input from all the parties.

“We’ve had a lot of problems with Dominion in the past,” said Stewart (R-At Large). “We have to protect the interests of citizens there at Somerset Crossing and Greenhill Crossing and make sure their properties are protected.”

Chuck Penn, a spokesman for Dominion, emphasized that the planning process has just begun. The utility has begun meeting with residents and has a public meeting scheduled for Sept. 10 at Battlefield High School. Dominion hopes to submit its plan for the line to the State Corporation Commission this fall, submit a plan for the substation to Prince William County next spring, and begin construction of the line and the substation in spring 2016, with electricity flowing by spring 2017.

“Nothing is cast in stone,” Penn said. “We’re in an information exchange with Haymarket and the surrounding community.”

Penn said the population of Haymarket “has more than doubled since 2000, and during that same time period, the demand for electricity has roughly tripled.” The 2012 population of Haymarket was estimated to be 1,900; it was about 900 in 2000.

“We’re looking at staying ahead of that,” Penn said. “In our business, we cannot wait until we need the power. You have to stay on top of the development.”

Penn also said, “We do have a customer in mind that is definitely going to add to the local growth.” But he declined to say who that might be. Stewart said he didn’t know, either.

David Leake, the mayor of Haymarket, said he “felt a little bit misled” by Dominion’s presentation to the Town Council on Monday. “They’re saying the growth of Haymarket is causing it. That’s not really the case. It really comes down to a Dominion customer that needs the electricity.”

Napoli said homeowners feared health problems, including cancer, from living near the high-voltage lines and worry that “it will cause massive drops in property values.” He said blue heron and other migratory species live on a pond near Somerset. Penn said that no link has been proved between power lines and health problems but that the utility would be responsive to environmental concerns.

Joe Pasanello, a Haymarket Town Council member, said there was a lack of honest outreach by Dominion and claimed that “their intent is to try to steamroll residents who live along the railroad right-of-way. It is irresponsible and an exercise of hubris by Dominion to present only one alternative and expect the community to toe the line, as it were.”