| Academic Resource and Referral Center | Academic & Science |
| Alcuin Research Resource Centre | Academic & Science |
| Acupuncture Research Resource Centre | Academic & Science |
| Advanced Radar Research Center | Academic & Science |
| Addiction Recovery Research Center | Academic & Science |
| Aquatic Resource Restoration Company | Business |
| Administrative Rules Review Committee | Community |
| Arlington Road Runners Club | Community |
| Alternative Reference Rates Committee | Community |
| Allied Rapid Reaction Corps | General |
| Ace Rapid Reaction Corps | General |
| Area Reference And Resource Center | General |
| Atlantic Ro Ro Carriers | General |
| Auto Rental Resource Center | General |
| Aligned Round Rock Curriculum | General |
| ASPIN Recruitment Retention Consortium | General |
| Administrative Regulations Review Commission | General |
| American Road Race of Champions | General |
| Auto Reference Resource Center | General |
| Auto Repair Reference Center | General |
| Asia Road Racing Championship | General |
| Aylesbury Recycling And Reuse Centre | Governmental |
| Appalachian Regional Recycling Consortium | Governmental |
| Allied Command Europe Rapid Reaction Corps | Governmental |
| Associate of the Royal Red Cross | Governmental |
| Animas River Russian Collusion | International |
| Advanced Recovery Rehabilitation Center | Medical |
| Advanced Railway Research Centre | Regional |
| Alaska Raptor Rehabilitation Center | Regional |
| Alaska Rural Rehabilitation Corporation | Regional |
| Africa Rainforest and River Conservation | Regional |
