Glass Beach, Port Townsend

What Seaglassmap found here

The only rich sea glass beach in America you can lawfully collect on, and it makes you earn it: a nine-kilometre round trip along the shore from North Beach County Park out to McCurdy Point, with the tide deciding whether you get back. There are few to no escape routes under the bluff, so read the tide table before you set out, not after. What is waiting is jewellery-grade glass, marbles and old china, with cobalt turning up in quantity. Start from the county park. The point itself is reached down a private road, so don't be tempted.