Prudhoe Bay Oil Field

The Prudhoe Bay Oil Field is the largest oil field in North America, located on Alaska’s North Slope between the National Petroleum Reserve–Alaska and the Arctic National Wildlife Refuge. Its discovery was confirmed on March 12, 1968, and production began in 1977 when the Trans-Alaska Pipeline was completed. The field covers 213,543 acres and originally held about 25 billion barrels of oil in place [1].

Discovery

Humble Oil, later part of Exxon, and ARCO confirmed the discovery on March 12, 1968, using the Prudhoe Bay State #1 well. ARCO was the operating partner. The well originally targeted the Lisburne limestone but also encountered gas and oil in the Sadlerochit formation [1]. The find was a turning point for Alaska’s economy.

Size and Reserves

The field is described as the largest in North America, covering 213,543 acres (86,418 hectares). It originally held about 25 billion barrels of oil in place, of which 16 billion barrels were estimated to be recoverable and about 4 billion remain [1].

Production History

Production began on June 20, 1977, when the Trans-Alaska Pipeline was completed, and oil moves through flow and transit lines to a pumping station at the head of the pipeline [1]. Output peaked in 1988; one section of the source gives 1.5 million barrels per day and another gives 1.97 million, so sources differ [1]. The infobox reports 319,013 barrels per day in 2023 [1].

Operators

BP operated the field until its 2019 sale of Alaska assets to Hilcorp, which is now the operator. ExxonMobil and ConocoPhillips were partners until August 2019 [1].

Location and Access

The field lies on the North Slope, between the National Petroleum Reserve–Alaska and the Arctic National Wildlife Refuge, and is reached by road from Fairbanks via the Elliott and Dalton Highways [1].

Nearby Fields

The Kuparuk River Oil Pool is part of the Milne Point Unit, about 35 miles west of Prudhoe Bay, and is not part of the Prudhoe Bay Unit [1].

Economic Importance

Prudhoe Bay oil underpinned Alaska’s state budget for decades, funded the Alaska Permanent Fund and led to the construction of the Trans-Alaska Pipeline, one of the largest private construction projects of its time. Its revenues transformed public services and the state’s finances after statehood.

The Search for Oil

Petroleum geologist Tom Marshall urged the state to select the Prudhoe Bay land, and Governor Bill Egan agreed in 1964. Early wells drilled from 1963 were dry, and most companies gave up by 1967. ARCO and Humble Oil made a final attempt in late 1967, and Prudhoe Bay State Well No. 1 struck oil [2]. Initial estimates put the field at 9.6 billion barrels, the largest North American discovery at the time and still the largest in the United States [2]. Later Wikipedia estimates are larger, with about 25 billion barrels originally in place and 16 billion recoverable [1], reflecting the different ways reserves are measured.

Cumulative Production

The field has produced about 12 billion barrels since 1977 [2]. Production has declined steadily since the mid-1990s, and the Trans-Alaska Pipeline now carries about a quarter of its 1980s peak [2]. The decline is the main reason that Alaska’s budget debates have focused on how to replace oil revenue.

State Revenue

From 1980 to 2016, oil revenue paid for most state government services in Alaska. Surplus revenue funds the annual dividend, which has been more than ,000 per Alaskan in recent years [2]. Falling oil prices and falling output have left the state with an uncertain fiscal future [2].

The Exxon Valdez Connection

The oil from Prudhoe Bay traveled by pipeline to Valdez and then by tanker. In 1989 the tanker Exxon Valdez released about 11 million gallons of Prudhoe Bay crude oil into Prince William Sound, one of the largest oil spills in United States history [2].

Reaching the Field

Visitors and workers reach the oilfield by road from Fairbanks via the Elliott and Dalton Highways, a route of several hundred miles, or by air [1]. The field and its supporting infrastructure form a large industrial complex on the Arctic coastal plain.

FAQs

When was oil discovered at Prudhoe Bay? The discovery was confirmed on March 12, 1968.

How big is Prudhoe Bay? It covers 213,543 acres and is the largest oil field in North America.

Who operates Prudhoe Bay? Hilcorp has been the operator since BP sold its Alaska assets in 2019.

How is the oil transported? Through the Trans-Alaska Pipeline, which began service in 1977.

How do you reach Prudhoe Bay? By road from Fairbanks via the Elliott and Dalton Highways.

Sources

1. Wikipedia: Prudhoe Bay Oil Field
2. NPR, “Alaska’s 40 Years of Oil Riches Almost Never Was” (2017).

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 12, 2026Researched and drafted with AI assistanceReport an issue