In the past few decades, numerous attempts have been made on modeling of salt tectonics and deciphering the geometry of salt domes, which is a key challenge in petroleum exploration. We have derived a 3D density model of the Wathlingen salt dome, situated in the southern part of the Northwest German Basin from joint modeling of reprocessed torsion balance measurements. Gravity, gravity gradients , curvature derived from horizontal gravity gradients , and horizontal directive tendency are jointly modeled to decipher the geometric structure of the salt dome. The model was constrained by geologic and borehole information. We found that the Wathlingen salt dome is a mushroom-structured salt body, which is 14-km long, 4–8-km wide extending up to depth. The top mushroom structure of the salt is horizontally spread up to . It would not have been possible to derive the complex 3D structure from modeling of gravity data alone.