| Official Name: | Rosario, Washington |
| Pushpin Map: | Washington#USA |
| Pushpin Label: | Rosario |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Washington |
| Subdivision Type2: | County |
| Subdivision Name2: | San Juan |
| Established Title: | Established |
| Established Date: | 1906 |
| Unit Pref: | Imperial |
| Timezone: | Pacific (PST) |
| Utc Offset: | -8 |
| Timezone Dst: | PDT |
| Utc Offset Dst: | -7 |
| Postal Code Type: | ZIP code |
| Blank Name: | FIPS code |
| Blank1 Name: | GNIS feature ID |
Rosario is an unincorporated community in San Juan County, in the U.S. state of Washington.
A post office called Rosario was established in 1906, and remained in operation until 1954.[1] The community takes its name from nearby Rosario Strait.[2]