No one is quite sure where the 1792 Ohio River low-water line is. Illinois claims it is about 100 feet into the river; Kentucky claims the entire Ohio River, bank-to-bank.

In the past, complaints concerning river rights came from Illinois residents who fished the Ohio River. But the stakes are higher now, and a ruling could affect a multimillion dollar operation at Metropolis, Ill. Players International Inc.'s riverfront and casino project.

The $18.5 million project will bring more than 600 jobs to the area and have a total payroll of more than $12 million early in 1993.

"This border dispute has been in the courts six years," said Jim Leach, a spokesman for the Illinois attorney general's office. "It will eventually have to be resolved in the courts."

The border case reached the U.S. Supreme Court in 1986, when Illinois complained that Kentucky officials were trying to force Illinois residents fishing in the river to have Kentucky licenses.

At that time Kentucky maintained that the Illinois-Kentucky border is and always has been the present low-water mark on the northerly shore of the Ohio River. Under that claim, the entire river is within Kentucky's jurisdiction.

Illinois contended the border rightfully is the low-water mark on its shore as it existed in 1792, when Kentucky became a state. That could give Illinois rights to a significant portion of the river that historically has been controlled by Kentucky.

The Supreme Court ruled in June 1991 in favor of Illinois, giving Illinois rights to a significant part of the river as it is today. The court, in a unanimous ruling, set the border at the low-water mark on the Illinois side as it existed in 1792 - rather than where it is today.

"The fishing flap has since been settled," said Leach. "The conservation departments of both states reached a reciprocal agreement concerning fishing rights on the Ohio."

Included in the Supreme Court ruling was a call for a "special master" to study the border dispute and work with both states in an effort to find where the 199-year-old low-water mark is. On average, the 1792 mark extends at least 100 feet into the water from the Illinois shore, although the distance from shore can vary from point-to-point along the length of the states' shared border.

"We know the state line will vary at given points along the river," said Leach. "At some points it could be close to the Illinois shore line and at some parts it could be farther out in the river."

The issue came up again last week when Kentucky Attorney General Chris Gorman told The Associate Press that Kentucky law allows the confiscation of gambling equipment in Kentucky and that Kentucky lays claim to virtually the entire Ohio river, bank-to-bank.

"At this point, we're refusing to grant the extra 100 feet into the river," said Gorman.

Similar disputes with Indiana and Ohio have been settled with Kentucky conceding that the boundary is about 100 feet into the river. But Gorman said better surveying techniques now exist and he has refused an offer from Illinois to reach the same boundary settlement.

Players International plans to move a restaurant barge and ticket center to the Metropolis riverfront next week, with the 1,200-passenger riverboat casino expected to start operations as early as mid-February, said company officials.

The schedule calls for the riverboat to present three-hour cruises during the day and evenings. The riverboat will be equipped with 650 slot machines and 38 table games like blackjack and roulette.

Kentucky law does not allow casino gambling.

David Fishman of Players International wasn't available for comments, but he said earlier he was not worried about operating in the Ohio.

"We don't perceive that as a problem, and believe we have enough room to operate our boat without going into Kentucky waters," he said in September. "We have made our determination on maps done by the Corps of Engineers."

Linda Mulcahy, a spokesperson for the Illinois Gaming Board, told the Southeast Missourian that regulators were familiar with the border issue when the license was granted to the Metropolis operation. "We believe the boat will stay within the Illinois limits," she said.

Mulcahy declined to speculate what might happen if a licensed gambling operation in Illinois is seized by Kentucky officials.

Gorman raised the possibility that a showdown could come before the games begin. The riverboat is being built in Louisiana and Gorman said it would probably have to pass through Kentucky waters on the way to its new home port.

Although most borders created by waterways are set in the middle of the water, a 19th century Supreme Court ruling held that when Virginia transferred control of the Northwest Territory to the federal government it retained all of the Ohio River up to the low-water mark on the river's north bank.

Illinois and Kentucky both were created from territory ceded by Virginia to the United States in 1783. Illinois became a state in 1818, 26 years after Kentucky.