2019 GC6

 is a very small near-Earth asteroid and potentially hazardous object of the Apollo group, approximately 20 m in diameter. It was detected by the Catalina Sky Survey at Catalina Station on 9 April 2019, a few days before it made its first-observed pass through the cislunar region at a distance of 136,000 miles, comparable to roughly half the average distance from the Earth to the Moon (0.58 LD).

Orbit and classification
is a member of the Apollo group of asteroids, which are Earth-crossing asteroids. They are the largest group of near-Earth objects with approximately 10,000 known members. It orbits the Sun at a distance of 0.91–1.29 AU once every 14 months (424 days; semi-major axis of 1.1 AU). Its orbit has an eccentricity of 0.18 and an inclination of 1° with respect to the ecliptic.

The body's observation arc begins with its first observation by the Mount Lemmon Survey on 31 March 2019, just a few days prior to its potential discovery observation by the Catalina Sky Survey.

Diameter and albedo
The dimensions of the asteroid are estimated to range between 7.5–30 m and has been compared to size of a house. Based on an magnitude-to-diameter conversion and a measured absolute magnitude of 26.5, measures between 15 and 28 meters in diameter for an assumed geometric albedo of 0.20 (siliceous) and 0.057 (carbonaceous), respectively.