| O U Medical Center | Oklahoma City, OK | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| O'Connor Hospital | Delhi, NY | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Oak Valley Hospital District | Oakdale, CA | Acute Care Hospitals | Government - Hospital District or Authority | 1 star |
| Oakbend Medical Center | Richmond, TX | Acute Care Hospitals | Government - Hospital District or Authority | 3 stars |
| Oakdale Community Hospital | Oakdale, LA | Acute Care Hospitals | Proprietary | 3 stars |
| Oaklawn Hospital | Marshall, MI | Acute Care Hospitals | Voluntary non-profit - Other | 4 stars |
| Oaklawn Psychiatric Center Inc | Goshen, IN | Psychiatric | Voluntary non-profit - Private | Not rated |
| Oakleaf Surgical Hospital | Altoona, WI | Acute Care Hospitals | Physician | Not rated |
| Oakwood Springs, LLC | Oklahoma City, OK | Psychiatric | Proprietary | Not rated |
| Oasis Behavioral Health Hospital | Chandler, AZ | Psychiatric | Proprietary | Not rated |
| Ocean Beach Hospital | Ilwaco, WA | Critical Access Hospitals | Government - Hospital District or Authority | 2 stars |
| Ocean Medical Center | Brick, NJ | Acute Care Hospitals | Voluntary non-profit - Other | 4 stars |
| Ocean View Psychiatric Health Facility | Long Beach, CA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Permian Basin | Midland, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Abilene | Abilene, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Alexandria | Alexandria, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Amarillo | Amarillo, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Baton Rouge | Baton Rouge, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Corpus Christi | Corpus Christi, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Deridder | Deridder, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Greater New Orleans | Kenner, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Jackson | Jackson, MS | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Katy | Katy, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Kentwood | Kentwood, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Lake Charles | Lake Charles, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Longview | Longview, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Lubbock | Lubbock, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Lufkin LLC | Lufkin, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Opelousas | Opelousas, LA | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Pasadena | Pasadena, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Tupelo | Tupelo, MS | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital of Waco | Waco, TX | Psychiatric | Proprietary | Not rated |
| Oceans Behavioral Hospital- Biloxi | Biloxi, MS | Psychiatric | Proprietary | Not rated |
| Oceans Hospital of Broussard | Broussard, LA | Psychiatric | Proprietary | Not rated |
| Ochiltree General Hospital | Perryton, TX | Critical Access Hospitals | Government - Hospital District or Authority | Not rated |
| Ochsner American Legion Hospital | Jennings, LA | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Ochsner Choctaw General | Butler, AL | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Ochsner Lafayette General Medical Center | Lafayette, LA | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Ochsner Laird Hospital | Union, MS | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Ochsner LSU Health Monroe | Monroe, LA | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Ochsner LSU Health Shreveport | Shreveport, LA | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Ochsner LSU Health Shreveport-St Mary Medical Cent | Shreveport, LA | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Ochsner Medical Center - Baton Rouge | Baton Rouge, LA | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Ochsner Medical Center Acute | New Orleans, LA | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Ochsner Medical Center-Hancock | Bay Saint Louis, MS | Acute Care Hospitals | Government - Local | 3 stars |
| Ochsner Medical Center-Kenner | Kenner, LA | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Ochsner Rush Hospital | Meridian, MS | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Ochsner Scott Regional | Morton, MS | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Ochsner St Anne General Hospital | Raceland, LA | Critical Access Hospitals | Voluntary non-profit - Other | Not rated |
| Ochsner St Martin Hospital | Breaux Bridge, LA | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Ochsner St Mary | Morgan City, LA | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Ochsner Stennis Memorial Hospital | De Kalb, MS | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Ochsner University Hospital and Clinics | Lafayette, LA | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Ochsner Watkins Hospital | Quitman, MS | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Oconomowoc Memorial Hospital | Oconomowoc, WI | Acute Care Hospitals | Voluntary non-profit - Private | 5 stars |
| Odessa Memorial Healthcare Center | Odessa, WA | Critical Access Hospitals | Government - Hospital District or Authority | Not rated |
| Odessa Regional Medical Center | Odessa, TX | Acute Care Hospitals | Proprietary | 3 stars |
| Ogallala Community Hospital | Ogallala, NE | Critical Access Hospitals | Government - Hospital District or Authority | Not rated |
| Ogden Regional Medical Center | Ogden, UT | Acute Care Hospitals | Proprietary | 3 stars |
| Ohio County Hospital | Hartford, KY | Critical Access Hospitals | Proprietary | 2 stars |
| Ohio Hospital for Psychiatry | Columbus, OH | Psychiatric | Proprietary | Not rated |
| Ohio State University State Health System | Columbus, OH | Acute Care Hospitals | Government - State | 3 stars |
| Ohio Valley Surgical Hospital | Springfield, OH | Acute Care Hospitals | Voluntary non-profit - Private | Not rated |
| Ohiohealth Mansfield Hospital | Mansfield, OH | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Ohiohealth Morrow County Hospital | Mount Gilead, OH | Critical Access Hospitals | Government - Local | Not rated |
| Ohiohealth O'Bleness Hospital | Athens, OH | Acute Care Hospitals | Voluntary non-profit - Other | 3 stars |
| Ohiohealth Shelby Hospital | Shelby, OH | Critical Access Hospitals | Voluntary non-profit - Private | 4 stars |
| OHSU Hospital and Clinics | Portland, OR | Acute Care Hospitals | Voluntary non-profit - Other | 3 stars |
| Okeene Municipal Hospital | Okeene, OK | Critical Access Hospitals | Government - Local | Not rated |
| Oklahoma Center for Orthopaedic & Multi-Sp | Oklahoma City, OK | Acute Care Hospitals | Physician | Not rated |
| Oklahoma City VA Medical Center | Oklahoma City, OK | Acute Care - Veterans Administration | Veterans Health Administration | 2 stars |
| Oklahoma Heart Hospital South, LLC | Oklahoma City, OK | Acute Care Hospitals | Physician | 5 stars |
| Oklahoma Heart Hospital, LLC | Oklahoma City, OK | Acute Care Hospitals | Physician | 4 stars |
| Oklahoma Spine Hospital | Oklahoma City, OK | Acute Care Hospitals | Physician | Not rated |
| Oklahoma State University Medical Center | Tulsa, OK | Acute Care Hospitals | Government - Hospital District or Authority | 2 stars |
| Oklahoma Surgical Hospital, LLC | Tulsa, OK | Acute Care Hospitals | Physician | 5 stars |
| Old Vineyard Youth Services | Winston Salem, NC | Psychiatric | Proprietary | Not rated |
| Olean General Hospital | Olean, NY | Acute Care Hospitals | Proprietary | 1 star |
| Olivia Hospital & Clinic | Olivia, MN | Critical Access Hospitals | Voluntary non-profit - Private | 2 stars |
| Olmsted Medical Center | Rochester, MN | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Olympic Medical Center | Port Angeles, WA | Acute Care Hospitals | Government - Local | 3 stars |
| Omaha VA Medical Center (VA Nebraska Western Iowa Healthcare System) | Omaha, NE | Acute Care - Veterans Administration | Veterans Health Administration | 4 stars |
| Omega Hospital, LLC | Metairie, LA | Acute Care Hospitals | Physician | Not rated |
| Onecore Health | Oklahoma City, OK | Acute Care Hospitals | Proprietary | Not rated |
| Oneida Health Hospital | Oneida, NY | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Onslow Memorial Hospital | Jacksonville, NC | Acute Care Hospitals | Government - Hospital District or Authority | 1 star |
| Opelousas General Health System | Opelousas, LA | Acute Care Hospitals | Government - Hospital District or Authority | 2 stars |
| Optim Medical Center - Screven | Sylvania, GA | Critical Access Hospitals | Proprietary | Not rated |
| Optim Medical Center - Tattnall | Reidsville, GA | Critical Access Hospitals | Proprietary | Not rated |
| Orange City Area Health System | Orange City, IA | Critical Access Hospitals | Voluntary non-profit - Other | 3 stars |
| Orange County Global Medical Center | Santa Ana, CA | Acute Care Hospitals | Proprietary | 2 stars |
| Orchard Hospital | Gridley, CA | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Oregon State Hospital Distinct Part | Salem, OR | Psychiatric | Government - State | Not rated |
| Orem Community Hospital | Orem, UT | Acute Care Hospitals | Voluntary non-profit - Private | Not rated |
| Orlando Health | Orlando, FL | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Orlando Health Bayfront Hospital | Saint Petersburg, FL | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Orlando Health Melbourne Hospital | Melbourne, FL | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Orlando Health Sebastian River Hospital | Sebastian, FL | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Orlando Health South Lake Hospital | Clermont, FL | Acute Care Hospitals | Government - Hospital District or Authority | 3 stars |
| Orlando Health St Cloud Hospital | Saint Cloud, FL | Acute Care Hospitals | Proprietary | 2 stars |
| Orlando Health-Health Central Hospital | Ocoee, FL | Acute Care Hospitals | Government - State | 3 stars |
| Orlando VA Medical Center | Orlando, FL | Acute Care - Veterans Administration | Veterans Health Administration | 5 stars |
| Oro Valley Hospital | Oro Valley, AZ | Acute Care Hospitals | Proprietary | 3 stars |
| Oroville Hospital | Oroville, CA | Acute Care Hospitals | Voluntary non-profit - Private | 1 star |
| Orthocolorado Hosp at St Anthony Med Campus | Lakewood, CO | Acute Care Hospitals | Proprietary | Not rated |
| Orthoindy Hospital | Indianapolis, IN | Acute Care Hospitals | Physician | Not rated |
| Orthopaedic Hospital at Parkview North | Fort Wayne, IN | Acute Care Hospitals | Voluntary non-profit - Private | Not rated |
| Orthopaedic Hospital of Wisconsin | Glendale, WI | Acute Care Hospitals | Physician | Not rated |
| Ortonville Area Health Services | Ortonville, MN | Critical Access Hospitals | Government - Local | Not rated |
| Osage Beach Center for Behavioral Health | Osage Beach, MO | Psychiatric | Proprietary | Not rated |
| Osborne County Memorial Hospital | Osborne, KS | Critical Access Hospitals | Government - Local | Not rated |
| Osceola Community Hospital | Sibley, IA | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| OSF Heart of Mary Medical Center | Urbana, IL | Acute Care Hospitals | Voluntary non-profit - Church | 3 stars |
| OSF Holy Family Medical Center | Monmouth, IL | Critical Access Hospitals | Voluntary non-profit - Church | 4 stars |
| OSF Little Company of Mary Medical Center | Evergreen Park, IL | Acute Care Hospitals | Voluntary non-profit - Other | 2 stars |
| OSF Sacred Heart Medical Center | Danville, IL | Acute Care Hospitals | Voluntary non-profit - Church | 2 stars |
| OSF Saint Anthony's Health Center | Alton, IL | Acute Care Hospitals | Voluntary non-profit - Church | 4 stars |
| OSF Saint Clare Medical Center | Princeton, IL | Critical Access Hospitals | Voluntary non-profit - Church | 2 stars |
| OSF Saint Elizabeth Mdl Ctr | Peru, IL | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| OSF Saint Katharine Medical Center | Dixon, IL | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| OSF Saint Luke Medical Center | Kewanee, IL | Critical Access Hospitals | Voluntary non-profit - Private | 4 stars |
| OSF Saint Paul Medical Center | Mendota, IL | Critical Access Hospitals | Voluntary non-profit - Church | 3 stars |
| OSF St Francis Hospital and Medical Group | Escanaba, MI | Critical Access Hospitals | Voluntary non-profit - Church | 4 stars |
| Osmond General Hospital | Osmond, NE | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Oss Orthopaedic Hospital | York, PA | Acute Care Hospitals | Proprietary | Not rated |
| Oswego Hospital | Oswego, NY | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Othello Community Hospital | Othello, WA | Critical Access Hospitals | Government - Local | Not rated |
| Otis R Bowen Center for Human Services Inc | Pierceton, IN | Psychiatric | Voluntary non-profit - Private | Not rated |
| Ottawa County Health Center | Minneapolis, KS | Critical Access Hospitals | Voluntary non-profit - Other | Not rated |
| Otto Kaiser Memorial Hospital | Kenedy, TX | Critical Access Hospitals | Government - Hospital District or Authority | Not rated |
| Ottumwa Regional Health Center | Ottumwa, IA | Acute Care Hospitals | Proprietary | 2 stars |
| Ouachita County Medical Center | Camden, AR | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Our Lady of Fatima Hospital | North Providence, RI | Acute Care Hospitals | Proprietary | 3 stars |
| Our Lady of Lourdes Memorial Hospital, Inc | Binghamton, NY | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Our Lady of Lourdes Regional Medical Center, Inc | Lafayette, LA | Acute Care Hospitals | Voluntary non-profit - Private | 3 stars |
| Our Lady of the Angels Hospital | Bogalusa, LA | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Our Lady of the Lake Regional Medical Center | Baton Rouge, LA | Acute Care Hospitals | Voluntary non-profit - Church | 3 stars |
| Our Lady of the Lake Surgical Hospital | Slidell, LA | Acute Care Hospitals | Physician | Not rated |
| Overlake Hospital Medical Center & Clinics | Bellevue, WA | Acute Care Hospitals | Voluntary non-profit - Other | 2 stars |
| Overland Park Reg Med Ctr | Overland Park, KS | Acute Care Hospitals | Proprietary | 4 stars |
| Overlook Medical Center | Summit, NJ | Acute Care Hospitals | Voluntary non-profit - Private | 5 stars |
| Overton Brooks VA Medical Center (Shreveport) | Shreveport, LA | Acute Care - Veterans Administration | Veterans Health Administration | 2 stars |
| Oviedo Medical Center | Oviedo, FL | Acute Care Hospitals | Proprietary | 3 stars |
| Owatonna Hospital | Owatonna, MN | Acute Care Hospitals | Voluntary non-profit - Other | 5 stars |
| Owensboro Health Muhlenberg Community Hospital | Greenville, KY | Acute Care Hospitals | Voluntary non-profit - Private | 4 stars |
| Owensboro Health Regional Hospital | Owensboro, KY | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |
| Owensboro Health Twin Lakes Medical Center | Leitchfield, KY | Acute Care Hospitals | Voluntary non-profit - Other | 3 stars |
| Ozark Health | Clinton, AR | Critical Access Hospitals | Voluntary non-profit - Private | 4 stars |
| Ozarks Community Hospital of Gravette | Gravette, AR | Critical Access Hospitals | Voluntary non-profit - Private | Not rated |
| Ozarks Healthcare | West Plains, MO | Acute Care Hospitals | Voluntary non-profit - Private | 2 stars |