It was discovered on 3 August 1991, by Belgian astronomer Eric Elst at ESO's La Silla Observatory site in Chile.
[2] Euphrates is one of very few bodies located in the 2:1 mean motion resonance with the gas giant Jupiter and belongs to the "marginally unstable" Griqua group.
[5] Based on an absolute magnitude of 13.9, it measures between 4 and 10 kilometers in diameter, assuming an albedo in the range of 0.05 to 0.25.
Since asteroids in the outer main-belt are mostly of a carbonaceous rather than of a silicaceous composition, with low albedos, typically around 0.06, its diameter is likely to be between 8 and 10 kilometers.
[4] As of 2017, Euphrates' effective size, its composition and albedo, as well as its rotation period and shape remain unknown.