The following is a list of unnumbered minor planets in chronological order of their principal provisional designation. Contrary to their numbered counterparts, unnumbered minor planets have a poorly determined orbit due to insufficient observational data. This also includes lost minor planets which have not been observed for many years, or even decades. As of August 2023, the Minor Planet Center (MPC) accounts for 676,755 unnumbered minor planets which represent 52% of the overall minor planet population. Unnumbered minor planets can be further divided into 129,103 single-opposition objects with short observation arcs, prone to mismatch and loss, and 547,652 objects that have been observed multiple times during opposition, when astrometric conditions are most favorable. The JPL Small-Body Database gives a running total of 676,786 unnumbered minor planets.
The tables below contain 115 objects with a principal designation assigned between 1927 and 1994. Additional partial lists cover the period from 1995 to 2004. Unnumbered minor planets detected after 2004 are not listed due to their large number. The orbital uncertainty parameter (U) ranges from low ("0") to very high ("9"). For some single-opposition objects no numeric uncertainty is given ("–"), with "E" indicating an estimated, rather than determined orbital eccentricity. Furthermore, a color code is used to indicate a body's basic dynamical classification, with additional information given in columns "class" and "description and notes" (especially for near-Earth objects, Jupiter trojans and distant objects). If available, mean diameters are taken from the latest NEOWISE publication, or, if not available, estimated based on an object's absolute magnitude and displayed in italics.