This paper reports what is believed to be the first direct observation of the drift of single fluxons through a superconductor. This has been achieved by using an ultrasensitive cryotron amplifier to sense the changes in persistent current which occur in a superconducting film loop when a fluxon is drifting into or out of the loop. The loop is deposited on an insulated superconducting ground plane; this decreases the inductance sufficiently so that the current changes induced by single fluxons entering or leaving the loop can be sensed. It has been found possible to nucleate single fluxons by current pulsing narrow films which are superimposed over but insulated from the loop. The fluxons are found to be nucleated at the intersections of the edges of the film loop with the superimposed films, and then swept into or out of the loop by the Lorentz force exerted by the loop current. The fluxon velocity component normal to this current has been measured for tin and is found to be less than a factor of two different from the values predicted by certain of the present theories of fluxon motion.