The political arm of the Fairfax County Chamber of Commerce endorsed Republican gubernatorial candidate Jerry W. Kilgore on Thursday, an unexpected show of support from a key business group in the state's most populous county.

The announcement came the same day that Kilgore picked up the endorsement of the National Rifle Association, whose backing he hopes will help energize voters in rural Virginia, where gun rights are highly valued.

But the support of the Fairfax chamber will help Kilgore highlight an issue critical in vote-rich Northern Virginia: transportation.

Members of the group's board of trustees, who participated in a closed-door meeting Thursday to discuss the endorsement, said that Kilgore's stance allowing local governments to raise their own taxes for road and rail projects led them to believe that he was more committed to helping Northern Virginia secure a dedicated source of funding for transportation.

Kilgore's Democratic opponent, Lt. Gov. Timothy M. Kaine, has said he would not support raising new money for transportation until the General Assembly locks up such funds with a constitutional amendment. In such a scenario, new money for transportation in a Kaine administration might not arrive until 2009.

"In terms of transportation, Jerry Kilgore had a plan," said Michael Lewis, chairman of the board of trustees for NOVABizPAC, the Fairfax chamber's political action committee.

"Although Tim Kaine talked about transportation, we felt it was a little disingenuous not to come to Northern Virginia with a clear plan on how he was going to fund transportation," Lewis added. "Jerry's plan wasn't perfect. But at least he started to address the specific funding aspect." Kilgore's plan would not allow the region to raise the transportation funds without a voter referendum.

The support from the chamber surprised several political observers because of the stances Kilgore has taken in the past on issues important to the business group. For instance, the chamber was a key supporter of the 2004 tax package for education, public safety and health care pushed in part by Kaine. Kilgore was a strident opponent of the plan.

In addition, in a debate between the two candidates held before the group last month, observers remarked on how Kaine gave a strong performance.

"It's surprising for two reasons," said Larry J. Sabato, director of the Center for Politics at the University of Virginia. "Kaine won the debate in Fairfax, and this is Mark Warner's base, and they're turning their back on Warner's chosen successor," Sabato said, referring to Gov. Mark R. Warner (D).

Kilgore, the former attorney general, who was traveling the state's rural stretches touting his NRA endorsement, said in a statement that the pair of endorsements amounted to a clear signal that his campaign is well received in diverse parts of the state.

"To receive the biggest endorsement in Fairfax County on the same day as we received the endorsement of the National Rifle Association is proof positive that our campaign is appealing to voters from every walk of life and every part of the state," he said.

Kaine's campaign remained confident that, despite the chamber's endorsement of Kilgore, Kaine would still receive strong support from the Northern Virginia business community. The campaign has criticized Kilgore's position on the regional referendum in the past, saying it would be just another tax increase.

Kilgore has said that although he does not support raising taxes in general, he would not stand in the way of regions that wished to do so.

"Hundreds of members of the Fairfax chamber saw the recent debate between Jerry Kilgore and Tim Kaine, and they are very clear on the kind of governor that Tim Kaine will be," said Delacey Skinner, Kaine's press secretary. "We feel like we have the support of businessmen and women across the state."

As for the NRA endorsement, Wayne LaPierre, the executive vice president and chief executive of the NRA said in an interview that his organization backed Kilgore largely for his support of several bills expanding gun owners' rights and gave him an "A" rating.

Kaine, the current lieutenant governor, said he was not surprised that the group backed Kilgore but said the decision does not mean he opposes gun rights.

"I'm a strong supporter of the Second Amendment. I'm a strong supporter of the right to hunt and fish," Kaine said in an interview.

Staff writer Michael D. Shear contributed to this report.

Political scientist Larry J. Sabato called the decision "surprising."