3255 Tholen was discovered on September 2, 1980 by David J. Tholen, who it was named after, at the Anderson Mesa Station.
3255 Tholen, provisional designation 1980 RA, is a stony asteroid, Mars-crosser and relatively fast rotator, that measures approximately 5.1 kilometers (3.2 miles) in diameter. 3255 Tholen E. Bowell Anderson Mesa Stn. 2 September 1980 (3255) Tholen David J. Tholen
(American astronomer) 1980 RA  1969 SD Mars-crosser It was discovered on 2 September 1980, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station in Flagstaff, Arizona. 
