Fortuna is a city on the northeast shore of the Eel River, approximately 9 miles from where it enters the Pacific Ocean, and is on U.S. Route 1…Fortuna is a city on the northeast shore of the Eel River, approximately 9 miles from where it enters the Pacific Ocean, and is on U.S. Route 101 in west-central Humboldt County, California, United States. The population was 12,516 at the 2020 census, up from 11,926 at the 2000 census.