Opponents of the drilling say it raises troubling questions about acceptable uses of publicly shared land - even when new technology allows rigs positioned outside park boundaries to reach petroleum pockets deep beneath the parks by drilling horizontally.
Sean Logan, director of the Ohio Department of Natural Resources, said parks get 40 percent of their money from fees related to camping, boating, beach access and other recreational activities. If drilling affects the panoramas or the noise level, these other revenue sources could start suffering, he said.
Drilling is still barred in national parks. But the reversal of some state bans coincides with efforts to expand exploration in other previously off-limits locations: offshore in coastal states, near Aztec ruins in New Mexico and in some urban parks.
Arkansas has signed a lease allowing drilling to begin under Woolly Hollow State Park. Pennsylvania saw its first drilling on state park property this spring.
In July, a circuit court judge in West Virginia ruled against the state environmental protection agency's attempt to block drilling under Chief Logan State Park. The first well in Living Desert Zoo and Gardens State Park in Carlsbad, N.M., was drilled in 2007.
The U.S. Geologic Survey monitors oil and gas activity nationally, though no organization tracks drilling that falls within the boundary of state parks, or how much oil and gas can be pulled from that land.
In western New York, retiree Jay Wopperer is fighting a proposal to drill in Allegany State Park, 65,000 acres of forested valleys south of Buffalo.
"I don't oppose drilling," said Wopperer, of Clarence, N.Y., who has led the Audubon Society's bird hikes in Allegany for 10 years. "But there are plenty of other places to drill in western New York. This is the people's park."
To drill, roughly two acres are cleared of trees and vegetation. Gravel roads are also required to access drilling masts about 120 feet high. Producers have in some cases put mufflers on machinery and reduced other noises, but there are still trucks and other related sounds.
Backers say that wellheads and nature trails can coexist, in part because of new technology reduces the environmental footprint of drilling operations.
In Ohio's Salt Fork State Park, much of the work would be by directional drilling, a technique that involves entering the surface at one location, making an underground turn and tunneling sometimes for miles underground to reach oil or natural gas pockets.
"You probably wouldn't even notice the drilling rigs. It's very, very environmentally sensitive and, at the same time, would produce a huge amount of revenue," said state Sen. Keith Faber, who is pushing a proposal to allow the first-ever drilling in Ohio state parks.
A state committee puts Ohio's estimated take from new drilling as high as $5 million a year. Ohio, with 11 percent unemployment and among the worst foreclosure rates in the country, needs the cash to offset declining tax revenues.
Ohio is not alone.
According to the latest figures from the nonpartisan Center on Budget and Policy Priorities, state budgets face a combined $163 billion shortfall in fiscal year 2010 even after making billions in cuts.
The money from drilling won't cure state shortfalls, but every office is being asked to find new revenue or face cuts, including parks.
Arkansas parks director Greg Butts said his state received about $200,000 in initial bonus payments by signing the deal allowing natural gas directional drilling under Woolly Hollow, cradled in the Ozark foothills. The lease doesn't allow drilling on park property.
On land sitting above massive natural gas reserves like the Marcellus shale, which spreads over four states including Ohio, new drilling techniques have created a lot more opportunities for companies like Oklahoma City-based Chesapeake Energy Corp.
"In our home state, in fact, one of our larger royalty owners is the Oklahoma Department of Wildlife Conservation," said spokesman Jim Gipson. "Many public entities are seeing that there is significant opportunity to create economic value from natural gas resource development while simultaneously protecting the environment."
Some states have balked, with lawmakers in Kentucky and Ohio allowing state-park drilling proposals to die this year. Looking solely at proceeds from drilling, some say, is missing the bigger picture and the greater harm.
In Pennsylvania, however, a state ban on surface drilling in state parks was unable to thwart private drilling in Goddard State Park because the company, Pittsburgh-based Vista Resources, owns the mineral rights.
Most state park directors still see drilling as contrary to their mission of leaving the land as pristine as possible, said Philip McKnelly, executive director of the National Association of State Park Directors.
Once that line is crossed, park officials say, there is no going back.
Right now, there is a huge glut of natural gas because of the recession and the new drilling techniques. Prices have plunged as a result. There is apprehension from some park directors that with any economic rebound, the pressure to drill on public lands will only grow stronger.
--- Associated Press writers Stephen Majors in Columbus and news researcher Monika Mathur in New York contributed to this report.