Your visit to secluded Obstruction Pass State Park, named for nearby Obstruction Island, takes you to not only the longest beach on Orcas but also one of the San Juans’ most unusual—a crescent of ocean-smoothed, marble-sized pebbles in rainbow colors. Hike in half a mile to one of the 80-acre park’s 11 first-come, first-served primitive campsites, land your kayak on Pebble Beach, or anchor out at one of three moorings. Many campsites overlook the water; vault toilets and fire pits are available.