On August 10, 2002, at 1330 central daylight time, a Cessna 210L, N3UF, piloted by a private pilot, sustained substantial damage while executing a precautionary landing near Lacon, Illinois. Visual meteorological conditions prevailed at the time of the accident. The business flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot and passenger reported no injuries. The flight departed Aurora Municipal Airport (ARR), Sugar Grove, Illinois, at 1300. The intended destination was Mount Hawley Auxiliary Airport (3MY), Peoria, Illinois. According to the pilot's written statement, while descending from cruise altitude he "noticed that the autopilot descend button had gotten progressively warmer. The last time I checked it, it was too hot to hold down. I turned off the autopilot and noticed that the panel around the autopilot was also very hot. I turned off the master switch thinking I may have the beginning of an electrical fire and started thinking of landing at the nearest airport. Within about a minute I smelled something hot or burning and I immediately picked out a field in which to land. I did not notice any smoke." The pilot reported he made the decision to perform the precautionary landing between 2,500 - 3,000 feet msl. The pilot stated, "I made a 130 degree turn to the east, pulled the mixture control and landed in the corn[field]." According to a written statement provided by the pilot's mechanic, the pilot reported the "instrument panel was so hot he could not hold his hand on it." The pilot reported to the mechanic that he had "smelled smoke and made a gear up landing in a cornfield." The airplane was located in a cornfield that was approximately 4 nautical miles northeast of the nearest airport, Marshal County Airport (C75), Lacon, Illinois. C75 has 2 runways, runway 13/31 (3,200 feet by 75 feet, asphalt) and runway 18/36 (2,200 feet by 50 feet, asphalt). According to the airplane mechanic who is rebuilding the airplane, there was no evidence of fire and/or smoke damage to the accident airplane. The mechanic also reported there were no discrepancies with the autopilot unit and/or system.