On August 30, 2021, about 0819 eastern daylight time, a Piper PA-28-161, N864ZLM, was substantially damaged during a forced landing at Grant-Valkaria, Florida. The private pilot and the pilot-rated passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the preflight inspection, departure, and climb phases of flight were normal and uneventful. She leveled off at 7,500 feet mean sea level and began to lean the mixture. While leaning, the engine rpm dropped below 1,000. She responded by increasing the mixture to full rich and applying full throttle; however, the engine did not respond. The airplane began to lose altitude rapidly and she tried to restart the engine to no avail. She declared an emergency, and air traffic control provided radar vectors to Valkaria Airport (X59), Valkaria, Florida. Unable to make the airport, she force-landed the airplane in a farm field. The airplane collided with a fence and a ditch before coming to a stop. The pilot and passenger exited the airplane and were met by first responders. Inspectors with the Federal Aviation Administration responded to the accident site and examined the wreckage. Both wings and the fuselage received substantial damage. There was no fire. The right-wing fuel tank contained about 17 to 18 gallons of fuel and the left tank was empty; however, the left tank was compromised by impact forces. The wreckage was recovered to an aircraft salvage facility for further examination. The engine crankshaft was rotated manually using the propeller; it rotated freely and no internal binding was noted. The engine appeared to be freshly painted and recently overhauled. The fuel and oil lines, spark plugs, the intake, and exhaust systems were in a like-new condition. The carburetor was fractured in half by impact forces. The top spark plugs were removed, and the propeller was rotated by hand; engine continuity was established through the engine drive train and the impulse couplings in the magnetos could be heard snapping. Compression was established on all cylinders. Other than the impact-damaged carburetor, the examination of the engine did not reveal evidence of a preexisting mechanical anomaly or failure.