New experience yesterday. I skipped out on the last hour of work yesterday to go to what I was told was a gem of an airport in the lewis and Clark national forest on the edge of the bob marshall wilderness. 3U7, Benchmark Montana, a back country strip that is a rarity in that it is 6000' and paved. Flight was going nice, flying over wilderness area, no logging roads or anything below, GPS tuned in to the airport, about an hour before sunset, i'm cruising along at 11,500. GPS is telling me i'm 6 miles away so the airport looks like its going to be in that canyon. I cant descend to much or else i'll have to fly around a mountain and then up in the canyon. There is a mountain to the east so I cant setup for a straight in to rwy 30 gonna have to setup a down wind for 30. One problem, I cant find the airport. the GPS was telling me it was right under me. I flew 3 circles around that canyon and never did find the airport. The sun blaring didn't help and I was having trouble seeing the ground. Never found the airport. Im sure it was down there. Im sure i could have descended down in the canyon and spotted it but i didn't want to wing it in the canyon not knowing the surrounding terrain at all. Im still lauging that I have GPS that flew me straight to the airport and I still couldn't find it. Luckily I saw that coming (well i knew i might get in a situation where I didnt want to land in the middle of nowhere, plus no fuel at the airport played a big part) so i had plenty of fuel to make it back home. On a side note coming back at 12,500 i contacted Spokane approach and they couldn't see me. I guess thats why they always terminate flight following when i'm in that area.