Info on Senior pass?

Discovery pass is only good for Washington State Parks. Turnbull is a National Park and doesn't recognize the Discover Pass. According to Turnbull's website you'll need a Senior Pass, The Senior and Access passes are good for the lifetime of the holder and make available (to the pass holder only) 50 percent discounts on some expanded amenity fees. You can purchase a Senior or any other pass from the Ranger Station at the end of the straight path after entering Turnbull Refuge. The price of the National Parks and Federal Recreational Lands Senior Pass, a lifetime entry pass for citizens age 62 and older, increased from $10 to $80 on Aug. 28, 2017. The passes for entry to Turnbull are as follows, U.S. Fish &Wildlife Service - Annual Pass valid at Turnbull National Wildlife Refuge, Military Annual Pass, Annual Pass, Access Pass, Senior Pass or a Migratory Bird Hunting and Conservation Stamp. This year Turnbull initiated the "Duck the Fee Station" program where annual and lifetime

It's a few bucks, young or old.

I'm not sure about a senior pass but I have a disability placard and that allows me to go into the parks without having to pay for them, otherwise I believe you need a Discovery Pass. I hope that helps.