It's a Franklin Mint token made in 1966, Rich. From the condition, I'd say it's from one of the collector sets. The have only nominal value... maybe $2-5 for someone who needs to fill a hole. Over 7000 were made.

66 is the year Riverside opened at what was then Southpoint, NV. Anderson's book says that when they got a post office near the casino, it was named Laughlin and they no longer used the "near Davis Dam" address. Marv says this is an error token as there never was a Davis Dam, NV. However, all 7000 say that, so it's not an error that was corrected [g].

BTW, The Gaming Table says that Riverside Casino in Davis Dam, NV opened and closed in 1977.... I'd say that's probably an error.