Mukhsha Ulus (Tatar: Мухша олысы, romanized: Muxşa olısı, lit.
'موحشا ﯘلىسى'), or Naruchat Duchy (Tatar: Наручат бәклегел, romanized: Naruçat bäklege, lit.
'ناروچات بەكلئگئل') was a subdivision of Golden Horde at the place of modern Mordovia, Penza Oblast and Tambov Oblast of Russia in 13th-15th centuries with the capital in Mukhsha.
The main territory of the ulus (district) was situated between rivers Sura and Tsna.
Population was mainly Mişär Tatars, and Moksha Mordvins.