On September 11, 1998, at 0558 mountain daylight time, a Cessna 180F, N4612U, registered to and operated by the pilot, was substantially damaged when it collided with a deer during the takeoff roll at Douglas, Wyoming. The airline transport-rated pilot, the sole occupant aboard, was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight being operated under Title 14 CFR Part 91. The flight was originating at the time of the accident. According to the pilot, he was taking off from Converse County Airport's runway 28 (6,750 feet x 100 feet, asphalt) in the predawn darkness, en route to Casper, Wyoming, about 47 miles to the west. As the airplane lifted off the runway, a small deer, weighing an estimated 75 pounds, struck the rear of the airplane. Because the airplane remained under control at all times, the pilot elected to continue to Casper, where he landed without incident. Examination of the airplane disclosed the leading edge of the left horizontal stabilizer was crushed inward and bent.