OLYMPIA, Wash. -- Washington's State Route 99 is now known as "The William P. Stewart Memorial Highway."
Stewart was one of Snohomish County's earliest African American settlers.
Before heading west, he volunteered to fight for the United States in the Civil War.
State lawmakers voted in favor of the change earlier this year, and the state's transportation commissioners officially approved it Tuesday afternoon.
"It's fantastic," said Marilyn Quincy, Stewart's great-granddaughter.
She still lives in Snohomish County.
Quincy never met her great-grandfather but said she was told he was a humble man.
"So he probably would have just been completely overwhelmed," said Quincy.
Adding two new signs to the highway will cost more than $5,000.