Geological Chronicle
Located on the Moon's far side to the east-southeast of Shayn and due north of Dante, Larmor is an impact crater spanning 99.49 kilometers in diameter. Its rim is broken across by the satellite crater Larmor Z, while the remaining rim is slightly worn, particularly to the southwest.
Near the midpoint of the otherwise relatively level interior floor are low hill features. Along the southern end, the inner wall is wider and displays terrace structures.
In 1970, the International Astronomical Union named the crater after physicist Joseph Larmor. About one and a half crater diameters to the southwest lies the fresh satellite crater Larmor Q, which features an impact melt splash pool at the bottom, outer rim melt lobes, and a ray system.