What is located several miles southeast of the city with a recorded a population of 76,693?
Arnold Lava Tube System: The Arnold Lava Tube System (or Arnold system) is series of lava tubes in Deschutes County, Oregon, of the United States. Bend, Oregon:  Bend recorded a population of 76,693 at the time of the 2010 U.S. Census, up from 52,029 at the 2000 census.
series of lava tubes