Pacific Beach is located in western Grays Harbor County, along the Pacific Ocean. It is bordered to the north by Moclips and to the south by Joe Creek. The CDP includes the neighborhood of Highland Heights, north of Pacific Beach proper. State Route 109 passes through the CDP, leading north through Moclips 11 miles (18 km) to its terminus at Taholah, and south 8 miles (13 km) to Copalis Beach. Hoquiam is 25 miles (40 km) to the southeast.
According to the United States Census Bureau, the Pacific Beach CDP has a total area of 1.2 square miles (3.2 km), of which 0.03 square miles (0.07 km), or 2.07%, are water.
