Clatsop County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 41,072. The county seat is Astoria. The county is named for the Clatsop tribe of Native Americans, who lived along the coast of the Pacific Ocean prior to European settlement. Clatsop County comprises the Astoria, OR Micropolitan Statistical Area, or Sunset Empire, and is located in Northwest Oregon.

The Astoria Riverfront Trolley is a 3-mile (4.8 km) heritage streetcar line that operates in Astoria, Oregon, United States, using former freight railroad tracks along or near the south bank of the Columbia River, with no overhead line. The service began operating in 1999, using a 1913-built streetcar from San Antonio, Texas. As of 2012, the service was reported as carrying 35,000 to 40,000 passengers per year and has been called a "symbol" and "icon" of Astoria. The line's operation is seasonal, normally during spring break and from May through September.