| Official Name: | Plymouth, Washington |
| Pushpin Label Position: | top |
| Pushpin Map: | USA Washington Benton County |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Washington |
| Subdivision Type2: | County |
| Subdivision Name2: | Benton |
| Timezone: | Pacific (PST) |
| Utc Offset: | -8 |
| Timezone Dst: | PDT |
| Utc Offset Dst: | -7 |
| Elevation Ft: | 292 |
| Coordinates: | 45.9344°N -119.3503°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 99346[1] |
| Area Code: | 509 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 1507501[2] |
Plymouth is an unincorporated community in Benton County, Washington, United States. Plymouth is located on the Columbia River across from Umatilla, Oregon. It is south of the Tri-Cities and is served by Interstate 82. It was named by early settlers who felt a nearby rock promontory resembled Plymouth Rock.[3]