Supporters of a proposed 10-mile parkway that would connect Prince William and Loudoun counties hit back this week after a group of state legislators announced their intent to fight the project.

In a joint statement, the Prince William and Loudoun chambers of commerce said six area Republican legislators who announced their opposition Monday to the road misrepresented facts and failed to stand up for the business community.

The planned road — commonly referred to as the Tri-County Parkway — would connect Interstate 66 in Prince William to Route 50 in Loudoun and go through a Civil War battlefield in Manassas. Supporters say it would help Dulles International Airport become a thriving cargo hub and provide a key connection for commuters in the growing localities.

Monday’s news conference was held by Del. Timothy D. Hugo (Fairfax). Fellow Republican Dels. Robert G. Marshall (Prince William), Michael J. Webert (Fauquier) and Sens. Richard H. “Dick” Black (Loudoun), Richard H. Stuart (Westmoreland) and Jill H. Vogel (Fauquier) joined Hugo to voice opposition to the project.

Hugo said that the road was “unnecessary,” would not help the area economically and would compromise protected rural land around the battlefield.

Legislators’ opposition is “deeply concerning,” said the statement from Rob Clapper and Tony Howard, presidents of the Prince William and Loudoun chambers. Both chambers have long supported the highway, which has been planned since the 1990s.

“We are gravely disappointed in the misinformation and apparent lack of concern for our region’s economic prosperity needs that was exhibited by our state elected representatives,” they said.

The news release said legislators misrepresented the fact that Prince William’s rural area would be protected because the road would be a “limited access” thoroughfare. That designation would mean there would not be many areas where commuters can get on and off the road.

The business community is “unified” behind the project, Clapper said in an interview.

“How do you grow out of something that’s been labeled a bedroom community and grow into a thriving economy?” he said of Prince William. “You’ve got to be able to bring in corporate headquarters and corporate communities.”

A key to doing that, he said, is a faster and more reliable way to get to Dulles Airport.

Marshall, who was at the news conference this week voicing opposition to the road, said that he has “little confidence in any claims that are being made on behalf of the parkway,” including whether it would be built with few access points.

He said that he asked the state to provide details about why the Virginia Department of Transportation declared the parkway a part of a statewide “corridor of significance,” a key designation that allows it to receive funding in the future.

Marshall says that there are better ways to move traffic toward Dulles, including building a bridge over Route 28 at Walney and Braddock roads.

Marshall said he wants to draw attention to the issue.

“I’m going to make sure that this becomes an issue in the governor’s race,” he said.