We report the discovery of a nearby star with a very large proper motion of 5.05"+/-0.03" yr-1. The star is called SO 025300.5+165258 and referred to herein as a high proper motion star (HPMS). The discovery came as a result of a search of the SkyMorph database, a sensitive and persistent survey that is well suited for finding stars with high proper motions. There are currently only seven known stars with proper motions greater than 5" yr-1. The spectrum and measured tangential velocity indicate that the HPMS is a main-sequence star with spectral type M6.5. Trigonometric and photometric parallaxes have been determined, yielding distance estimates of 2.4+0.7-0.4 pc (lower limit) and 3.6+/-0.4 pc, respectively. If the former is correct, the HPMS ranks third in the list of nearest stellar systems. If the latter is correct, it is 17th. A more precise trigonometric parallax measurement is expected to be completed near the end of the year.