Oil was discovered in Prudhoe Bay, Alaska, on March 12, 1968, by ARCO and Exxon, revealing the largest oil field in North America and the 18th largest in the world. However, production didn't begin until 1977, following the completion of the Trans-Alaska Pipeline System, which was built to transport crude oil 800 miles south to the port of Valdez. This discovery reshaped Alaska's economy, contributing over 17 billion barrels of oil since production began and generating billions in revenue for the state.