174 Phaedra is a sizable, rocky main belt asteroid that was discovered by Canadian-American astronomer James Craig Watson on September 2, 1877, and named after Phaedra, the tragic lovelorn queen in Greek mythology.

The asteroid is orbiting the Sun with a period of 4.84 years and an eccentricity of 0.14.

Lightcurve data obtained from Phaedra indicates a rather irregular or elongated body.

Photometric observations of this asteroid at the Shadowbox Observatory in Carmel, Indiana, during 2009 gave a light curve with a period of 4.96 ± 0.01 hours.

[3] The asteroid's pole of rotation lies just 5–16° away from the plane of the ecliptic.