Dominion Virginia Power has decided it will not install high-voltage transmission lines along a wooded nine-mile stretch of the Washington & Old Dominion Trail in Loudoun County, lawmakers announced yesterday.

Had the utility proceeded with its much-opposed plans, 110-foot steel towers would have spiked the popular path, known for its leafy shade and wildlife. A 50-foot swath required on each side of the electrical towers would have devastated the forested trail, which has about 35 feet of trees on each side of its narrow asphalt path, said Gary N. Fenton, executive director of the Northern Virginia Regional Park Authority. That's about 26,000 trees, he said.

The utility announced its concession Thursday in a letter addressed to state Sens. William C. Mims (R-Loudoun) and H. Russell Potts Jr. (R-Winchester) and Del. Joe T. May (R-Loudoun), who held yesterday's news conference. All had strongly opposed the plans.

Elected officials and residents said they viewed Dominion's decision as an incremental victory because two miles of the trail in the southeastern edge of Leesburg are still available as potential sites.

Dominion officials said the expansion is necessary to serve rapidly growing electricity demands in the western part of the county. Although the utility has the required easements to construct lines along the trail, it first must receive approval from the State Corporation Commission.

The commission considers aesthetic and environmental factors, in addition to feasibility, cost and effect on the region's transmission grid, said Ken Schrad, a spokesman.

Last spring, Dominion engineers who study consumer demand identified western Loudoun as a spot particularly vulnerable to power outages. They predicted that as demand begins to overwhelm the existing system, towns including Purcellville, Hamilton and Round Hill could face serious interruptions in service if a power line is knocked out. The engineers recommended installing a high-voltage transmission line by summer 2007, and the utility identified the trail as a possible site. Construction takes about a year to complete, utility authorities said.

Anticipating opposition, the utility began holding public workshops in May to gauge response to its plans. Numerous elected officials denounced the proposal, as did local residents and trail users, who formed a grass-roots group, Save the Trail. The organization gathered about 5,000 signatures on its Web site during the past two months to protest the plans, said Barbara Notar, president of the volunteer group.

Dominion -- with more than 2 million customers, the state's largest utility -- had planned to submit its application to the state regulatory commission by November.

But after the public outcry, the utility decided to delay its submission until spring 2005, after it identifies alternate paths for the lines, said Le-Ha Anderson, the utility's spokeswoman.

Some residents of Kincaid Forest and Beauregard Estates, the remaining neighborhoods tagged as potential sites for the transmission lines, attended yesterday's news conference with posters urging Dominion to give up the last two miles of the trail as well.

"Go the extra mile (or two) to save the trail," read Laurie Gessaman's poster. The Kincaid Forest resident's 2-year-old son, Jackson, who sat in a stroller, held a smaller version of her sign. "This is where people live," she said, comparing her portion of the trail with the section that runs through downtown Leesburg.

Dominion will repeat the public workshops in the next few months after it identifies alternate routes for the power lines, Anderson said.

Plans for towers along the Washington & Old Dominion Trail, such as those in Vienna, had encountered opposition from residents and elected officials.