We took some time in May to trek out to the real Northern California - Crescent City, Eureka, Redding, and Chico. These towns are all several hundred miles north of San Francisco, which really is located closer to the middle of the state (north-south wise, at least).
Crescent City is a small town (~3000 population) about 20 miles from the Oregon border, and is probably most well known for having been severely damaged by the 1964 Alaska earthquake by a tsunami. The harbor here was also hit recently by the Japanese 9.0 earthquake on 11 March 2011, which spared the town, but wiped out the harbor along with the several dozen fishing boats that call Crescent City home. Damage from the tsunami has been cleaned up, but the harbor area needs to be rebuilt, and the fishing fleet repaired or replaced.
The day we arrived was a break in the rainy weather which this area is known for - in fact, we had clear weather for two of the three days we were there, and merely overcast skies the third.
Crescent City makes a great base for exploring Redwoods National Park (which begins just south of town), along with the coastal ranges of mountains.