On November 15, 2005, approximately 1830 mountain standard time, a Cessna 172L, N2870Q, operated by Fremont Motor Company, was substantially damaged when it impacted terrain during a forced landing 4 nautical miles northeast of Sweetwater County Airport (RKS), Rock Springs, Wyoming. Night visual meteorological conditions prevailed at the time of the accident. The business flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The private pilot reported no injuries. The cross-country flight departed Lander, Wyoming, approximately 1745. According to the NTSB Pilot/Operator Aircraft Accident Report Form (6120.1/2) submitted by the pilot, he departed Rawlins, Wyoming (RWL), on the morning of the accident and had flown to Powell, Wyoming, (POY) for a business meeting. The pilot stated that he departed POY approximately 1600, and flew to Lander, Wyoming (LND). He departed LND for RKS approximately 1745. He stated that 5 miles from the airport, he turned his landing light and carburetor heat on. Subsequently, both electrical and engine power were lost. The pilot stated he announced a "Mayday" call over the radio and performed a forced landing in hilly, rough terrain. The airplane nosed over during the forced landing, coming to rest inverted in a ravine. Both wings were bent down and wrinkled and the left main landing gear assembly separated from the fuselage. The nose wheel separated from the strut and the firewall was winkled. The airplane was recovered and relocated to a hangar in Greeley, Colorado. During recovery, one quart of fuel was recovered from the left wing. No further evidence of fuel was noted. An examination of the engine revealed no anomalies that would have precluded the engine from producing power prior to impact. The airplane master switch had been left on and the battery was dead. The airplane battery was replaced and the electrical system functioned properly. An examination of the remaining systems revealed no anomalies. In a telephone interview with the pilot, he stated that after the impact, he egressed through the front windscreen. The pilot stated that he could immediately smell fuel in the cabin and was able to hear it dripping from the airplane. The pilot stated that he visually verified full fuel tanks prior to departure from RWL, and during his preflight in POY, measured 15 to 16 gallons of fuel in each tank. Fuel consumption calculations, based on calm winds, revealed that the flight activity of the day should have consumed 29 gallons of fuel, leaving approximately 9 gallons on board. The pilot stated that he did not obtain a weather briefing, did not obtain winds aloft, and did not calculate the fuel consumption for the flight.