Bayrische Ostmark was a German Gau, an administrative division unit. It was formed in 1933 and included former Gau Oberfranken and Gau Niederbayern-Oberpfalz. Gau Bayrische Ostmark was commonly referred to as Ostmark. The city of Bayreuth was its main city.
Marks using the term Bayrische Ostmark or Ostmark were used until 1945.
Generally, Gau was an administrative unit of the NSDAP, German Nazi party. Later it was also an administrative division of the state. This administrative division was used until 1945.