Umatilla County, Oregon
Stafford Hansell Government Center in Hermiston
Location within the U.S. state of Oregon
Oregon's location within the U.S.
|Founded||September 27, 1862|
|• Total||3,231 sq mi (8,370 km2)|
|• Land||3,216 sq mi (8,330 km2)|
|• Water||16 sq mi (40 km2) 0.5%%|
| • Estimate |
|• Density||20/sq mi (9/km2)|
|Time zone||UTC−8 (Pacific)|
|• Summer (DST)||UTC−7 (PDT)|
Umatilla County (//) is a county in the U.S. state of Oregon. The county seat is Umatilla. In 2005, 73,878 people lived there.  Archived 2010-06-29 at the Wayback Machine The county includes 3,231 square miles (8,369 km2) of which 3,215 is land and the rest is water.