When the current state highway numbering system was first posted in January 1964, SR 407 started at Jct US 830 NW of Cathlamet and followed the Elochoman River into the Willapa Hills, where SR 407 ended. US 830 in the area became SR 4 in 1968. Effective April 1, 1992, SR 407 was dropped from the state highway system.
Before 1964, SR 407 had been SSH 12D.
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