Abraham Lincoln's patent was an invention to buoy and lift boats over shoals and obstructions in a river. Abraham Lincoln conceived the invention when on two occasions the boat on which he traveled got hung up on obstructions. Lincoln's device was composed of large bellows attached to the sides of a boat that were expandable due to air chambers. Filed on March 10, 1849, Lincoln's patent was issued as Patent No. 6,469 later that year, on May 22. His successful patent application led to his drafting and delivering two lectures on the subject of patents while he was president.
Lincoln was at times a patent attorney and was familiar with the patent application process as well as patent lawsuit proceedings. Among his notable patent law experiences as a result of his patent was litigation over the mechanical reaper; both he and his future Secretary of War, Edwin Stanton, provided counsel for John Henry Manny, an inventor. The original documentation of Lincoln's patent was rediscovered in 1997.