In the small coastal town of Stokkseyri, you will find a small, but charming campground. It includes a washing machine, a small common room, showers (available for a fee of 300 ISK), and a very peaceful, clean environment.
If you’re coming from the town of Selfoss, turn left off the main road (away from the sea) at this location (GPS: 63.835508, -21.060240). It’s easy to miss, and you might find yourself driving back and forth even in such a small town.