Statement of Significance (as of designation - December 20, 1989):
The 1950 Lightship WAL-604, along with her sister WAL-605, is the best representative of the last class of lightships built under the auspices of the U.S. Coast Guard. Although these vessels closely resembled earlier lightships in external appearance, they were a distinct departure in terms of the rest of their construction. Of the lightships built after 1939, WAL-604 retains the best integrity and is associated with the nationally significant station off the Columbia River Bar. She was retired in 1979 as the last Columbia station lightship, as well as the last on the Pacific Coast.