The private pilot was on a local passenger flight in conjunction with a wilderness lodge operating under Title 14, Code of Federal Regulations Part 91, when the accident occurred. The pilot said that during landing at an off-airport site he was in a left base to final turn when the left rudder became unresponsive. He said that he was able to level the wings with the ailerons just before the airplane impacted the ground. The pilot reported that the takeoff and earlier flight had been uneventful, but after the accident he and the passenger noted that the left rudder cable retaining bolt was missing. The left wing and fuselage received substantial damage during the impact with terrain. The pilot reported that the rudder cable connection is routinely inspected prior to every flight, and that prior to the accident flight no discrepancy was noted.