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.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.