Arcata is a small university town on Humboldt Bay — progressive, a little quirky, and genuinely pleasant to spend time in. It's home to Cal Poly Humboldt (formerly Humboldt State University), which gives the town its energy and its politics: Arcata has been governed by the Green Party and has declared itself a sanctuary city, banned Styrofoam, and built one of the country's first ecological wastewater treatment wetlands. For a place of 18,000 people, it has an outsized sense of itself, and mostly lives up to it.
The Arcata Plaza at the center of town is the best thing about Arcata — a proper public square with a farmers market, good coffee shops, and independent bookstores. The surrounding streets are walkable and human-scaled in a way that most California towns aren't. The Jacoby Building on the Plaza's northeast corner is the oldest surviving commercial building in the city, dating to 1857.
On the edge of Humboldt Bay, the Arcata Marsh is a world-class birding site and a landmark in ecological design — the city's wastewater treatment facility, reconceived as a wildlife sanctuary. From the campus, Redwood Park begins where the quad ends, with old-growth coast redwoods reachable in minutes. If you're anywhere in the area on Memorial Day weekend, don't miss the Kinetic Grand Championship — a three-day race of elaborately engineered human-powered sculptures from Arcata to Ferndale, one of the most genuinely fun spectacles in California.