The U.S. Supreme Court yesterday left standing a lower-court ruling ordering Exxon Corp. to pay $2.1 billion in damages for overcharging for crude oil from a large east Texas oil field.

The ruling by a special appeals court -- which the Supreme Court, without comment, chose not to review -- ordered the highest monetary damage award ever upheld on appeal against an American corporation. Pennzoil Corp. last year won a $10.53 billion damage award against Texaco Inc. for interfering with Pennzoil's attempts to buy Getty Oil Co., but that verdict is under appeal.

Exxon, the nation's largest company, said it would pay the $2.1 billion after it studies the court's decision. The money will go to the U.S. Treasury to be distributed to states for energy conservation programs. The amount each state will receive will be determined by the Department of Energy.

If distributed under an existing federal formula, DOE officials said Virginia could gain about $50 million; Maryland, $35 million and the District of Columbia, $4.6 million.

The $2.1 billion penalty imposed on Exxon was based on charges brought by DOE eight years ago. DOE contended that Exxon reaped huge profits by improperly interpreting federal oil price regulations between 1975 and 1981.

"We are extremely disappointed with the U.S. Supreme Court's decision," said Exxon Chairman Clifton C. Garvin Jr. Repeating Exxon's claims throughout the court suit, Garvin said, "it has always been Exxon's policy to abide by government rules and regulations. Even when there have been questions about the language in the rules, we have sought to interpret them, in consultation with government officials, in a manner consistent with the government's stated purpose or intent."

In a related action, DOE announced yesterday it had reached a $315 million agreement with Atlantic Richfield Co. to settle overpricing charges brought by the government last year. Although it agreed to make the payments, Arco didn't admit any wrongdoing.

The government had contended that the alleged Arco overcharges were accomplished through oil trades with smaller oil-trading concerns, including Marc Rich & Co. In October 1984, Marc Rich pleaded guilty to fraud in its oil trading.

Garvin said the Supreme Court ruling will have no additional impact on Exxon's 1985 earnings because the company already had taken adequate steps to cover the costs of any adverse ruling.

Among those steps was a total of $1 billion that the company already had written off to cover this and other pricing disputes with the government. Exxon officials said that sum should be sufficient because the effect of the judgment would reduce some of the taxes Exxon paid during price controls. As a result, Exxon said it hoped to get some tax refunds from the government.

The company also hopes to recover some of its costs from other oil companies and individuals that had an interest in the disputed oil field in Texas. About 2,500 companies and individuals had interests in the field, but Exxon controlled about two-thirds of its production.

To pay the $2.1 billion, Garvin said the company will use available funds as well as short-term borrowing.

Coming at a time when oil prices are dropping sharply, the ruling will nonetheless have a significant impact on Exxon, particularly its cash flow, said Frederick P. Leuffer Jr., a financial analyst with Cyrus J. Lawrence in New York. Yet, Leuffer added, given the company's huge size, "it really won't crimp their style."

Sanford Margoshes, an analyst with Shearson Lehman Brothers Inc., added, "While anyone else would have a conniption, Exxon can handle it rather painlessly. With their enormous size, tremendous earning power and low outstanding debt, they will be taking it in stride."

The company's earnings for 1985 are expected to be released today. For 1984, it earned $5.5 billion on revenue of $97.3 billion.

Trading in Exxon's stock prices yesterday appeared unaffected, closing 37.5 cents higher at $51.25.

DOE will oversee the distribution of the $2.1 billion, parceling out money according to each state's use of petroleum products between 1975 and 1981 when the price of oil was controlled by the federal government. Reimbursement directly to Exxon's customers that were overcharged was ruled out by the special Temporary Emergency Court of Appeals, set up to resolve disputes over federal price controls. The court found that it would take a full-scale audit of the entire petroleum industry to find all of the customers who should receive damages from the improperly priced oil.

Under the court ruling, the money is to be used for energy conservation programs, such as weatherizing schools, hospitals and low-income property, or to help poor families pay their fuel bills. However, DOE officials said the agency was reviewing its regulations to see if some of the money could be spent for broader conservation uses, such as mass transit and highway construction and maintenance.

Paul Massicot, director of Maryland's Energy Administration, said the state has a special trust fund to invest any of the money it receives from the government's petroleum overcharge cases. The money is invested so it can be used over a long time, with the interest being doled out yearly, primarily for weatherization projects, Massicot said.

In the District, "That money has been targeted to be spent for energy purposes," said Thomas Simms, special counsel to the District's corporate counsel. "But, specifically what, we'll have to work out."

The Temporary Emergency Court of Appeals found that Exxon overcharged its customers $895.5 million between 1975 and 1981 by improperly classifying oil from what was once one of the nation's largest oil fields, Hawkins Field in east Texas.

Exxon has claimed that it was permitted by the regulations to sell oil from the field as "new" oil rather than "old" oil. So-called "new" oil, at the time, was selling for about twice the price of "old" oil that was covered by strict price controls.

The $2.1 billion award includes interest charges on the $895.5 million. DOE also had sought a civil penalty, arguing that Exxon knowingly violated price control regulations. But U.S. District Judge Thomas F. Flannery ruled against the punitive damages, saying Exxon never tried to hide how it calculated oil prices in Hawkins field.

Exxon officials have expressed concern that the $2.1 billion price tag would increase if Exxon customers who bought the disputed Hawkins Field oil file their own lawsuits to collect the money directly. But it was unclear yesterday whether any of the major customers, such as refineries and airlines, would make such a move, saying it was too early to make such a decision.

The $2.1 billion award is by far the largest decision the government has won against an oil company for violating federal price control rules set up after the 1973 Arab oil embargo sent petroleum prices soaring. Controls were removed eight days after President Reagan assumed office in 1981.

DOE still is prosecuting cases involving suspected violations that took place during those six years. About 400 other suits still are pending.