List of unnumbered minor planets: 1999 U–Y

The "List of unnumbered minor planets: 1999 U–Y" refers to a compilation of minor planets (also known as asteroids) that were discovered in the year 1999 and that have not yet been assigned a permanent number by the International Astronomical Union (IAU). Minor planets are typically given a provisional designation upon discovery, which includes the year of discovery followed by a letter and possibly a number denoting the order in which they were discovered during that year.