Bad Niedernau is located 3 km (1.86 mi) southwest of Rottenburg am Neckar in the Neckar-valley with an elevation from 430 to 475 m. The area of the district is 410 hectares.

The following territories adjoin to Bad Niedernau, clockwise beginning in the north they are: Rottenburg (town), Weiler, Schwalldorf and Obernau (all in the admin.

Weiler, Schwalldorf and Obernau are districts of Rottenburg am Neckar.

In order to that Bad Niedernau is among the smaller districts of Rottenburg.

The former municipality of Bad Niedernau has awarded the honorary citizenship to Kilian von Steiner (Banker) in 1891.