Charlie- Welcome to OFF. Yes, Big Cliff is the body of water between Detroit Dam and Big Cliff Dam. It has trout and whitefish in it, among other species, and is a very scenic body of water. There is a small boat landing in the form of an unimproved gravel ramp at the Detroit Poerhouse exit. It was closed for a while, so I don't know if it is in service right now or not. Powerbait, worms and lures all work well, and some big trout have been taken out of the lake. Big Cliff usually isn't stocked until June, so it is mostly holdover fishing right now. The body of water is open all year for trout fishing under the Oregon regs.
Good luck,