Sinus Concordiae (
latin for "Bay of Harmony") is a bay (
sinus) on the
Moon that lies along the eastern edge of the
Mare Tranquillitatis. Along its northern border is an area called the
Palus Somni, while the southern border is an area of irregular terrain that contains the ruined crater
Da Vinci. The selenographic coordinates of this bay are 10.8° N, 43.2° E, and it has an overall diameter of 142 km.