185 Eunike is a dark and very large main-belt asteroid. It was discovered by C. H. F. Peters on March 1, 1878, in Clinton, New York and named after Eunike, a Nereid in Greek mythology whose name means 'happy victory'. The name was chosen to celebrate the Treaty of San Stefano (1878).
This object is orbiting the Sun at a distance of with an eccentricity of 0.129 and an orbital period of 4.53 years. Its orbital plane is inclined at an angle of 23.2ð to the plane of the ecliptic. Using infrared measurements, the diameter has been measured at . It has a primitive carbonaceous composition.
Based upon photometric observations made between 2010 and 2014, this asteroid has a rotation period of 21.812 hours and a brightness variation of 0.08 in magnitude. At opposition, the absolute magnitude was measured at 7.45. It displays a hemispheric albedo dichotomy similar to that on 4 Vesta.
As of 17 September 2020, there have been thirteen observed occultations of stars by Eunike.