Marth is a small lunar impact crater located in the northwest part of the Palus Epidemiarum. It was named after German astronomer Albert Marth. To the northwest is the crater Dunthorne, and to the southwest lies Ramsden. This feature lies in a system of rilles named the Rimae Ramsden, and an interrupted branch passes only a few kilometers to the south of the rim. Marth is unusual for having a double rim, with a smaller inner crater concentric to the outer rim. The smaller crater is located near the center of the larger rim, giving the feature a bullseye appearance.