Charon and Pluto form a planet-satellite system, sometimes referred to as a double dwarf planet system. Charon is the largest of Pluto's five moons, 754 miles (1,214 km) across. Pluto is about 1,400 miles wide. The distance between them is about 12,200 miles (19,640 km). 

Charon is half the size of Pluto and is the largest known moon. In a phenomenon called mutual tidal locking, the surfaces of Charon and Pluto face the same direction, always facing each other.

The New Horizons spacecraft, one of NASA's Solar System explorations, obtained a high-resolution colour image of Charon just before it came closest to Pluto on 14 July 2015.

In the image, Pluto's moon Charon is in the centre. The north (upper) polar region of the usually grey moon appears reddish. Impact craters are scattered across the moon's surface and a ridge diagonally separates its upper half from its lower half.