Last I recall they put up no trespassing signs below the damn because they were worried about terrorists blowing up the damn and ruining the water supply. Don't know how true that excuse is, but you can easily access the area but your not supposed hang out there.
This information is a public crowdsourcing effort between the Access Fund,
and Mountain Project. You should confirm closures, restrictions, and/or related dates.
----------------UPDATE------------------------ I did a little online research and it looks like the state rebuilt the dam in 2005. I'm not sure if all the sandstone got blown up or if it's more accessible than ever. Someone will have to do some exploring (I moved away so I can't) and let us know. The shale rock seen in the picture is crap. Its too chossy to climb well. I tried to climb by the old power plant below the dam years ago (1995-ish) on top rope from some rebar spikes on a ledge. It was cool, but had to have the belayer stand 40' from the edge of the cliff to avoid all the falling broken holds! If anyone has some pics it would be cool nostalgia to get them posted. I'll try to find my pics and get them scanned.
---------------------------------------------- Sunny and Shady areas. Sandstone rock. Lots of good rock, some super sketchy rock. A plethora of bolted leads exist here including roofs and I remember some 5.11's and harder. I only climbed 5.10 and less when I went there, so I am sure there are moderate climbs as well. I'm not sure how old the bolts are, but they are mostly from the 80's I would assume. Fairly secluded area since it is sort of off limits. I was there over 10 years ago, so someone will have to post what's going on now and if it is feasible to climb there again. I would suggest trying to locate the area itself before committing a day to climbing, since it may be underwater or fenced off. It was very easy to find when we went there, just check below the dams on Lake Tenkiller. Its under one of them (if there are more than 1 that is). Be WARY of POLICE and some SKETCHY ROCK if it is indeed still closed!
5 minute approach. Drive to Lake Tenkiller Damn and there is a service road that takes you down below the dam. It was not paved last I was there (1997). Park below dam by the creek. Go up to the dam, I mean litterally touching the spillover point base. The sandstone walls there are where all the climbs are. Unless the bolts were all chopped, you should see tons of bolted climbs on the walls all about 40-70ft tall.
I have a friend that lives right near there. If I remember right they were building the new dam quite a ways away from the old dam, and we were guessing they would stop using the old one (the one with the climbing) altogether but we never made sure. I mean we climbed at the dam one night (er bouldered the starts) while they were building the other dam and it didn't look like they had plans for the one we were in. I need to head back out there or if anyone else has info leave a little comment here.