Crescent City is closest, but the only flights that land there are direct from Oakland. If you can connect through Oakland and that works for you great. Arcata (about 35-40 miles south of the park) has direct flights to more locations (including San Fran and LA). The fog at either airport can be brutal, especially in the summer months. Don't plan for anything urgent the day after you fly into or out of either airport. I usually end up connecting through SFO and it's best to leave yourself a couple hours in case of delays. They have some nice restaurants and if you really want to kill time wander over to the international terminal to check out the cool murals on the walls.
McKinleyville,Ca. It's north of eureka, major airport!!! Also small craft airport in Eureka it's self
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