Quhistan

Quhistan (Persian:قهستان‎‎) or Kohistan (کهستان, "mountainous land") was a region of medieval Persia (Iran), essentially the southern part of Khurasan. Its boundaries appear to have been indeterminate, and the term generally seems to have been applied loosely. The area tended to be ruled as part of Khurasan however, experience some periods of autonomy.