“The residents in these areas have used that road for decades,” said Assistant Utah Attorney General Mark Ward. “We're seeking to enforce our rights on that road, recognizing that there are some wonderful places down there, places worth cherishing, but we don't have a way to get there.”

The state quietly notified the Bush administration last month that it planned to sue, claiming ownership of the road under a Civil War-era statute that gives states and counties control of historically used roads that cross federal land.

Salt Creek Road is an unpaved, ungraded Jeep trail that crisscrosses Salt Creek, the third-largest source of water in the park. A tributary canyon is home to Angel Arch, a popular destination in the park.

The Park Service's management plan, issued in 1995, allowed limited off-road traffic for about seven miles beyond Peekaboo Campground and a mile up the Angel Arch canyon.

In 1998, a federal judge said continued travel would permanently impair the park resources and closed the road. In August 2000, the 10th U.S. Circuit Court of Appeals disagreed and instructed the court to re-examine the record.

However, in the period the road was closed to traffic, vegetation grew in along parts, and the U.S. Fish and Wildlife Service designated sections of Salt Creek Canyon as critical habitat for the threatened Mexican spotted owl in 2001.

In June, the Park Service determined that any off-road traffic in Salt Creek Canyon would damage the park's resources and closed the road, prompting San Juan County to threaten the department with a lawsuit.

The state followed suit in a notice to the Interior Department on July 19, although there was no public announcement of the action.

Assistant Utah Attorney General Ralph Finlayson refused to release a copy of the notice or provide a date of the filing, saying the state considers such communication a part of settlement discussions and exempt from public disclosure.

There is a six-month waiting period before the state can commence a lawsuit against the government. Ward said the state anticipates it will intervene in the county's lawsuit, using its legal and financial resources to try to reopen the road.

Disputes over ownership of the roads and trails crossing federal lands have festered in Utah for years. In April 2003, then-Gov. Mike Leavitt negotiated an agreement with Interior Secretary Gale Norton that he said he hoped would resolve some of the disagreements.

But since then Utah has only submitted one claim to a road, the Weiss Highway in Juab County, which proved to be fraught with inaccuracies that may force its withdrawal by the state.

The Salt Creek road could not be claimed under the Leavitt agreement because it did not apply to roads in national parks.

The state's decision to invest its resources litigating the Salt Creek road does not mean the state is abandoning the Leavitt agreement, Ward said. Instead the state hopes to use both litigation and Leavitt's negotiated agreement to claim roads it believes should be in state or county ownership.