When the current state highway numbering system was first posted in January 1964, SR 831 started at Jct US 830 just east of the Cowlitz River Bridge in Kelso and headed NE to I-5 Exit 40. US 830 was dropped from the US highway system in 1968. Former US 830 west of I-5 was renumbered SR 4. SR 831 was renumbered SR 431.
Before 1964, SR 831 had been a branch of PSH 12.
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