18880 Toddblumberg (provisional designation 1999 XM₁₆₆) is a background asteroid from the outer region of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 10 December 1999, by LINEAR at the Lincoln Laboratory's Experimental Test Site, near Socorro, New Mexico, United States.^[4] The asteroid was named after Todd Blumberg, a 2003 ISEF contest awardee.^[2]

Toddblumberg orbits the Sun in the outer main-belt at a distance of 2.6–3.8 AU once every 5 years and 9 months (2,096 days). Its orbit has an eccentricity of 0.18 and an inclination of 10° with respect to the ecliptic.^[1] The first precovery was taken at Palomar Observatory (DSS) in 1953, extending the body's observation arc by 46 years prior to its official discovery observation at Socorro.^[4]

Although discovered by LINEAR, Toddblumberg is not a near-Earth asteroid. Its closest approach to the Sun (perihelion) is about double the maximum distance of 1.3 AU that qualifies an asteroid as "near-Earth".^[5]

This minor planet was named for Todd James Blumberg (born 1984), a student at the Plano Senior High School in Plano, Texas, who won the Intel International Science and Engineering Fair (ISEF) award for his microbiology project in 2003.^[2][7]

Since 2001, hundreds of secondary school students who have won awards at science fairs have had asteroids named after them.^[8][9] The approved naming citation was published by the Minor Planet Center on 30 August 2004 (M.P.C. 52648).^[10]