206 Hersilia is a fairly large Main belt asteroid.

The asteroid was named after Hersilia, Roman wife of Romulus.

It is classified as a primitive, dark carbon-rich C-type asteroid.

Measurements made with the IRAS observatory give a diameter of 101.72 ± 5.18 km and a geometric albedo of 0.06 ± 0.01.

By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 97.99 ± 7.40 km and a geometric albedo of 0.06 ± 0.02.