Oso has no famous person on record yet
The longest list of any town in Washington belongs to Yakima, with 65. After Yakima, the next longest list in Washington is Bellingham’s, with 53. 210 towns in Washington have at least one famous person on record.
Who’s listed here
Famous people come from Wikidata (people whose birthplace is Oso), checked against each person’s English Wikipedia article and ranked by how many Wikipedia languages cover them. Nobody born in Oso has passed that check yet, and nobody born within 35 miles is listed.
From Wikidata and Wikipedia: people whose birthplace is Oso and whose English Wikipedia article agrees, ranked by how many Wikipedia languages cover each person. People known mainly for crimes, and adult performers, aren’t listed. “The usual town” = everyone born in the towns gathered so far.