- Saltwater State Park is a 137-acre (55 ha) plot of second-growth timber on Puget Sound in the city of Des Moines, Washington, United States. The main attraction is 1,445 feet (440 m) of saltwater beachfront, including a sandy swimming beach in the southwest corner, and rocky tideflats along the west with a submerged artificial reef that is popular with scuba divers.