Chesapeake Energy Corporation is an American petroleum and natural gas exploration and production company headquartered in Oklahoma City, Oklahoma. The company was founded in 1989 by Aubrey McClendon and Tom L. Ward with only a $50,000 initial investment. McClendon named the company due to his love of the Chesapeake Bay region. Ward later left the company to found SandRidge Energy.

The company's properties are divided into two operating segments: the Southern Division and the Northern Division.

The northern division, which accounted for 42% of total production volumes in 2015 and 39% of total proved reserves at December 31, 2015, includes the acreage in the following areas:

The southern division, which accounted for 58% of total production volumes in 2015 and 61% of total proved reserves at December 31, 2015, includes the acreage in the following areas:

In 2015, the company produced 679 thousand barrels of oil equivalent (4,150,000 GJ) per day, which was 72% natural gas, 17% petroleum, and 11% natural gas liquids.

As of December 31, 2015, the company had 1.504 billion barrels of oil equivalent (9.20×10 GJ) of estimated proved reserves, of which 73% was natural gas and 27% was petroleum and natural gas liquids.

The company was founded in 1989 by Aubrey McClendon and Tom L. Ward with only a $50,000 initial investment. McClendon named the company due to his love of the Chesapeake Bay region. Ward later left the company to found SandRidge Energy.

By the time the company went public via an initial public offering in 1993, it was valued at $25 million.

Focusing on a strategy of drilling horizontal natural gas wells in unconventional reservoirs, the company built a sizable position in the Golden Trend and Sholem Alechem fields of South-central Oklahoma and in the Giddings field of Southeast Texas.

In the mid-1990s, the company attempted to extend the Austin Chalk play into western and central Louisiana but struggled to do so.

In 1997, the company wrote down the value of its assets by over $200 million (approximately equal to shareholder's equity at the time) due to low commodity prices and implemented a turnaround plan.

The rise in natural gas prices in the early 2000s allowed the company to focus drilling in areas that were previously not economically feasible. The company focused on unconventional drilling in carbonates, tight sandstone, and shale particularly in the Barnett Shale, Fayetteville Shale, and Marcellus Shale.

In 2006, Chesapeake was added to the S&P 500, replacing Dana Holding Corporation.

In 2008, Chesapeake announced its discovery of the Haynesville Shale in East Texas and northwestern Louisiana.

The company celebrated its 20th anniversary in 2009 by partnering with Orange County Choppers to create the world’s first chopper powered by compressed natural gas.

In June 2012, the company appointed Archie W. Dunham as chairman, replacing Aubrey McClendon, who retained his position as CEO. Dunham, who retired as chairman of ConocoPhillips in 2004, was appointed in response to shareholder concerns about corporate governance issues under McClendon's watch.

In December 2012, the company sold midstream assets for $2.16 billion.

On April 1, 2013, Aubrey McClendon was forced to leave the company when revelations that McClendon had taken a personal stake in Chesapeake wells and then used those investments as collateral for up to $1.1 billion in loans from banks that also financed the company.

In May 2013, Robert Douglas Lawler was named as McClendon's successor. At the time of the announcement, Lawler was the senior vice president of international and deepwater operations at Anadarko Petroleum. Steven Dixon, Chesapeake's chief operating officer, acted as interim CEO during the replacement search period and, at the time of his appointment in late March, a three-person office of the chairman, consisting of Dixon, Chairmen Archie Dunham and Chief Financial Officer Domenic Dell'Osso, was formed.

In 2013, Chesapeake sold 55,000 net acres in the Northern Eagle Ford Shale and 9,600 net acres in the Haynesville Shale to EXCO for aggregate proceeds of $1 billion.

In 2014, Chesapeake sold a large portion of its oil and gas assets in the Marcellus Shale and Utica Shale to Southwestern Energy for net proceeds of $4.975 billion. The transaction included approximately 413,000 net acres and 1,500 wells in northern West Virginia and southern Pennsylvania. Net production of the sold assets was 57,000 barrels of oil equivalent per day in December 2014.

In 2014, the company also sold additional midstream assets for $520 million.

In September 2015, the company announced layoffs of hundreds of people in Oklahoma City.

On March 2, 2016, former CEO and co-founder Aubrey McClendon died in a single-occupant single-vehicle crash when he drove his vehicle straight into a concrete bridge embankment in Oklahoma City. It occurred the day after a Justice Department federal grand jury had indicted McClendon for violating antitrust laws during his leadership at Chesapeake.

In mid-2012, the U.S. Department of Justice began an investigation into whether Encana, Canada's largest natural gas company, "illegally colluded with Chesapeake Energy Corp to lower the price of Michigan exploration lands during a public land auction in May 2010." Encana's internal investigation determined in 2012 that it did not collude with Chesapeake.

The Federal investigation ended in 2014.

On June 5, 2014, the state of Michigan filed felony fraud and racketeering charges against Chesapeake Energy, alleging that the company canceled hundreds of land leases on false pretenses after it sought to obtain oil and gas rights. Michigan attorney general Bill Schuette claimed that the company "obtained uncompensated land options from these landowners by false pretenses, and prevented competitors from leasing the land." Chesapeake Energy disputed all charges.

In 2015, the company settled related lawsuits by agreeing to pay $25 million as compensation to landowners with leases.

The company faces thousands of lawsuits in Texas regarding the alleged under-payment of royalties due to individuals that rented land to the company.

On March 1, 2016, a US Justice Department federal grand jury indicted Aubrey McClendon, co-founder and ex-CEO of the company for allegedly rigging the bidding process for land leases while CEO of the company from December 2007 through March 2012. The indictment says McClendon orchestrated a conspiracy in which two oil and gas companies, not named in the indictment, colluded not to bid against each other for the purchase of land in northwestern Oklahoma. According to the indictment, the companies would decide ahead of time who would win bids, with the winner then allocating an interest in the leases to the other company, eliminating open competitive bidding. The Justice Department said this was the first case resulting from a continuing federal antitrust investigation into price fixing, bid rigging, and other anti-competitive conduct in the petroleum industry.William J. Baer, assistant attorney general for the Justice Department's antitrust division, said "His actions put company profits ahead of the interests of leaseholders entitled to competitive bids for oil and gas rights on their land. Executives who abuse their positions as leaders of major corporations to organize criminal activity must be held accountable for their actions.”

McClendon died the next day, on March 2, 2016, in a single-occupant single-vehicle crash when he drove his vehicle straight into a concrete bridge embankment. Later that day, the Oklahoma City Police said it was too early to say if the collision was intentional. The charges were dropped by the Justice Department as a result of the death.

In 2004, then CEO Aubrey McClendon contributed $450,000 to the campaign of Tom Corbett for attorney general of Pennsylvania. These funds were credited as giving Corbett a narrow win in the election. When Corbett eventually became governor of Pennsylvania, he was very supportive of Chesapeake's fracking activity in Pennsylvania, and Pennsylvania was the only state without a severance tax on drillers, despite the fact that the budget for education was being reduced.

In 2008, then CEO Aubrey McClendon formed American Clean Skies Foundation, a non-profit foundation focused on selling the virtues of natural gas. The foundation was funded by the company and by McClendon. The foundation was criticized for doing nothing but pushing Congress to pass policies that benefited the company and McClendon's business interests.

In 2013, the Environmental Protection Agency levied a fine of $3.2 million on a subsidiary of the company and forced it to spend $6.5 million "to restore 27 sites damaged by unauthorized discharges of fill material into streams and wetlands".

On April 19, 2011, due to a failed seal assembly in a wellhead, the company lost control of a natural gas well in the Marcellus shale that was being fracture stimulated, causing a large spill of salt water and hazardous chemicals, such as 2-butoxyethanol and methanol, into the surrounding countryside. By April 22, 2011, the leak had been stemmed.

The state of Maryland announced its intention to sue the company for violation of the Resource Conservation and Recovery Act and the Clean Water Act since fracking fluids from the well blowout wound up in the Chesapeake Bay.

In 2015, the company was fined $1.4 million in Pennsylvania for a landslide caused by the company in 2011 that resulted in clogged waterways.

In 2014, the company was ranked #51 on Fortune Magazine’s 100 Best Companies to Work For List.

In 2009, at the annual Platts Global Energy Awards, the company was named the 2009 Energy Producer at the Year and received the Industry Leadership Award. The company was also a finalist in the Deal of the Year, CEO of the Year, and Community Development Program of the Year categories. In 2012, the company received an Award of Excellence.

In 2007, the company was named the “Best Managed Oil-and-Gas Company” by Forbes Magazine.

In 2011, Chesapeake Energy agreed to a 12-year naming rights partnership with the Oklahoma City Thunder for naming and branding rights of the Chesapeake Energy Arena at a cost of $3 million per year, with annual increases of 3%.