The Long Beach Peninsula is an arm of land on the southern coast of the state of Washington in the United States. Entirely within Pacific County, it is bounded on the west by the Pacific Ocean, the south by the Columbia River, and the east by Willapa Bay. Leadbetter Point State Park and Willapa National Wildlife Refuge are at the northern end of the peninsula and Cape Disappointment is at the southern end, with Pacific Pines State Park located in between. Cape Disappointment State Park west of Ilwaco, part of the Lewis and Clark National Historical Park, was the westernmost terminus for the Lewis and Clark Expedition. A monument designed by Maya Lin as part of the Confluence Project was dedicated there in 2005. The Long Beach Peninsula is known for its continuous sand beach 28 miles (45 km) in extent on the Pacific Ocean side, claimed to be the longest beach in the United States. It is a popular vacation destination for people from Seattle, Washington (165 miles (266 km) distant) and Portland, Oregon (115 miles (185 km) distant).

Cannon Beach is a city in Clatsop County, Oregon, United States. The population was 1,690 at the 2010 census. Cannon Beach is a popular coastal tourist destination in Oregon, famous for Haystack Rock, a 235 ft (72 m) sea stack that juts out along the Pacific Coast. In 2013, National Geographic listed Cannon Beach as "one of the world’s 100 most beautiful places."

The city of Tillamook is the county seat of Tillamook County, Oregon, United States. The city is located on the southeast end of Tillamook Bay on the Pacific Ocean. The population was 5,231 at the 2020 census.

Grays Harbor County is a county in the U.S. state of Washington. As of the 2010 census, the population was 72,797. Its county seat is Montesano, and its largest city is Aberdeen. Grays Harbor County is included in the Aberdeen Micropolitan Statistical Area.