The Columbia Bar is a system of bars and shoals at the mouth of the Columbia River spanning the U.S. states of Oregon and Washington. It is one of the most dangerous bar crossings in the world, earning the nickname Graveyard of the Pacific. The bar is about 3 miles (5 km) wide and 6 miles (10 km) long.

The Columbia River is the largest river in the Pacific Northwest region of North America. The river forms in the Rocky Mountains of British Columbia, Canada. It flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is 1,243 miles long, and its largest tributary is the Snake River. Its drainage basin is roughly the size of France and extends into seven states of the United States and one Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any river entering the Pacific outside of Asia, and the 36th greatest discharge of any river in the world.