Alphabetical company index for letter/character "O", page 17 of 22
- Oroville Hospital
- Oroville School District
- Oroville Union High - School District
- Orrick R-Xi School District
- Orrington Public Schools
- Orrstown Financial Services Inc.
- Orrville City School District
- Orsu Metals Corporation
- Orsus Xelent Technologies Inc.
- ORTEC International USA
- Orthocolorado Hospital at St Anthony Med Campus
- Orthofix International N.V.
- Orthoindy Hospital
- Orthologic Corp.
- Orthopaedic Hospital at Parkview North
- Orthopaedic Hospital of Wisconsin
- OrthoPediatrics Corp.
- Orthovita Inc.
- Orting School District
- Ortonville Area Health Services
- Ortonville Public Schools
- Orvana Minerals Corporation
- Osage Bancshares Inc.
- Osage City School District
- Osage Co. R-I
- Osage Co. R-Ii
- Osage Co. R-Iii
- Osage Community School District
- Osage County
- Osage County, MO
- Osage County, OK
- Osage Hills School District
- Osage School District
- Osakis Public School District
- Osawatomie School District
- Osborn Elementary District
- Osborn R-O School District
- Osborne County
- Osborne County Memorial Hospital
- Osborne County School District