HARRISBURG — Only days before more than 24,000 state employees could be furloughed because of a state budget impasse, agencies that would be the hardest-hit scrambled Thursday to alert Pennsylvanians to the potential closings of 120 state parks and scores of motor-vehicle licensing centers across the state.

Unless Democratic Gov. Ed Rendell and Republican leaders in the state Senate resolve differences that have kept the state without a budget since Sunday, all the parks will be closed Monday night. Park officials will advise any lingering campers Monday that they must leave by midnight, said Christina Novak, spokeswoman for the state Department of Conservation and Natural Resources.

At the 3,000-acre Presque Isle State Park in Erie, located on a sandy peninsula that juts into Lake Erie, mariners who keep their watercraft in the 498-slip marina would be allowed access to their boats, but could not take them in or out of the marina, if the furloughs are implemented, said assistant park manager Mike Mumau. Letters about the potential restrictions were expected to go out to boaters by today, he said.

Presque Isle is Pennsylvania's busiest state park, and it attracted nearly 27,000 visitors for its Fourth of July celebration, Mumau said.

The threatened partial state government shutdown "is just something that we're being positive about," he said. "We're hoping for the best possible outcome" from the sluggish budget discussions in Harrisburg.

By far the largest number of possible furloughs would be in the Pennsylvania Department of Transportation, where nearly 11,000 employees would be idled, including most of the workers at PennDOT's huge Harrisburg office center.

PennDOT would not open its 71 driver licensing centers and 26 photo-only centers Monday if the furloughs are implemented. Drivers could renew licenses or registrations over the Internet, but any action that requires visiting one of the centers would have to wait until normal operations resume, said PennDOT spokesman Rich Kirkpatrick.

In that event, "you can't take a (license) photo. You can't take a driver's test," Kirkpatrick said.

Of the roughly 78,000 full-time state employees under Rendell's jurisdiction, only those whose jobs are considered "noncritical" are targeted for the unpaid furloughs. Notices to those workers began going out Tuesday.

Nearly 52,000 workers with "critical" responsibilities, including state police and prison guards, would continue to work and be paid on time. The rest — about 2,000 top administration officials — would continue to work but would not be paid until a new budget is in place.

More than 2,300 employees face furloughs in the conservation department — more than in any other agency except PennDOT.

PennDOT planned to post a public notice about the effects of the potential furloughs on its Web site today, but the conservation department had no plan to follow suit.

A letter explaining the situation was expected to be hand-delivered Thursday to the parks to be distributed among overnight campers and concession operators, Novak said. Also, the department planned to alert the thousands of people with camping reservations by phone or e-mail "when we get final word" that the furloughs will occur, she said.

Some campers unaware of the budget stalemate who have camping reservations for next week may not learn about the park closures until they arrive at the park, Novak acknowledged.

About 12,000 reservations are pending over the next 11 months, most of them during the summer vacation season, Novak said.