The asteroid was discovered on 10 March 1988, by Japanese amateur astronomers Masaru Arai and Hiroshi Mori at Yorii Observatory (875) in central Japan.
[2] Yorii orbits the Sun in the outer main-belt at a distance of 2.3–3.8 AU once every 5 years and 4 months (1,960 days).
[3][9] In October 2013, American astronomer Brian Warner obtained a rotational lightcurve of Yorii from photometric observations taken at his Palmer Divide Observatory (716), Colorado.
Lightcurve analysis gave a well-defined rotation period of 6.669 hours with a brightness variation of 0.26 magnitude (U=3).
Yorii is located in the Ōsato District of the Saitama Prefecture in Japan's central Kantō region.