| 3RC | Ramblin Riders Riding Club | |
| 41N8 | For One Night | |
| 5HS | 5 Hertford Street | |
| AAAC | Aurora Area Apple Core | |
| AAC | Arlington Aquatic Club | |
| AAC | Animal Awareness Club | |
| AACC | Abe Ani Combat Club | |
| AACCC | Antique Auto Club of Cape Canaveral | |
| AACCC | Afro American Club of Citrus County | |
| AADC | Auburn Area Democratic Club | |
| AAFC | Association of Australian Football Clubs | |
| AAFU | American Association of Firearms Users | |
| AAHC | Anti Anti Hentai Club | |
| AARC | Ambler Area Running Club | |
| AARC | Ashburn Area Running Club | |
| AARC | Anne Arundel Radio Club | |
| AARC | Ak-Sar-Ben Amateur Radio Club | |
| AARC | Aruba Amateur Radio Club | |
| AARSC | Ajax Adult Recreational Soccer Club | |
| AASC | Against Anti Sonic Clubs | |
| AATC | Ann Arbor Track Club | |
| AAWC | Axis Allies World Club | |
| AAYC | Ann Arbor Yacht Club | |
| ABAC | Atlanta Broadcast Advertising Club | |
| ABAC | Avila Bay Athletic Club | |
