| OCHD | Oakland County Health Division
| Others |
| OCHD | Obsessive Compulsive Hoarding Disorder
| Others |
| OCHD | Ocean County Health Department
| Others |
| OCHD | Off Center Harbor Disorder
| Others |
| OCHD | Ogle County Highway Department
| Others |
| OCHD | Okmulgee County Health Department
| Others |
| OCHD | Oneida County Health Department
| Others |
| OCHD | Onondaga County Health Department
| Others |
| OCHD | Onslow County Health Department
| Others |
| OCHD | Orange County Harley Davidson
| Others |
| OCHD | Orange County Health Department
| Others |
| OCHD | Ottawa Carleton Health Department
| Others |