| 5.2 km || |-id=519 bgcolor=#fefefe | 21519 Josephhenry || || || May 23, 1998 || Socorro || LINEAR || — || align=right | 3.8 km || |-id=520 bgcolor=#d6d6d6 | 21520 Dianaeheart || || || May 23, 1998 || Socorro || LINEAR || — || align=right | 8.7 km || |-id=521 bgcolor=#E9E9E9 | 21521 Hippalgaonkar || || || May 23, 1998 || Socorro || LINEAR || — || align=right | 6.2 km || |-id=522 bgcolor=#E9E9E9 | 21522 Entwisle || || || June 19, 1998 || Socorro || LINEAR || RAF || align=right | 3.3 km || |-id=523 bgcolor=#d6d6d6 | 21523 GONG || || || June 26, 1998 || Goodricke-Pigott || R. A. Tucker || — || align=right | 10 km || |-id=524 bgcolor=#d6d6d6 | 21524 || || — || June 21, 1998 || Kitt Peak || Spacewatch || KOR || align=right | 4.5 km || |-id=525 bgcolor=#E9E9E9 | 21525 || || — || June 25, 1998 || Kitt Peak || Spacewatch || DOR || align=right | 12 km || |-id=526 bgcolor=#E9E9E9 | 21526 Mirano || || || June 30, 1998 || Farra d'Isonzo || Farra d'Isonzo || — || align=right | 4.1 km || |-id=527 bgcolor=#E9E9E9 | 21527 Horton || || || June 24, 1998 || Socorro || LINEAR || EUNmoon || align=right | 5.0 km || |-id=528 bgcolor=#fefefe | 21528 Chrisfaust || || || June 24, 1998 || Socorro || LINEAR || — || align=right | 3.6 km || |-id=529 bgcolor=#d6d6d6 | 21529 Johnjames || || || June 26, 1998 || Socorro || LINEAR || ITH || align=right | 6.1 km || |-id=530 bgcolor=#E9E9E9 | 21530 Despiau || || || June 26, 1998 || Anderson Mesa || LONEOS || — || align=right | 13 km || |-id=531 bgcolor=#E9E9E9 | 21531 Billcollin || 1998 OS || || July 20, 1998 || Caussols || ODAS || — || align=right | 6.3 km || |-id=532 bgcolor=#d6d6d6 | 21532 || 1998 OY || — || July 20, 1998 || Caussols || ODAS || — || align=right | 7.1 km || |-id=533 bgcolor=#d6d6d6 | 21533 || || — || July 26, 1998 || La Silla || E. W. Elst || KOR || align=right | 6.4 km || |-id=534 bgcolor=#E9E9E9 | 21534 || || — || July 26, 1998 || La Silla || E. W. Elst || HOF || align=right | 12 km || |-id=535 bgcolor=#d6d6d6 | 21535 || || — || July 26, 1998