| Business | Phone |
| League Of Women Voters 6109 63rd Ave, Riverdale 20737 | (301) 864-1016 |
| National Apostolate Po Box 218, Riverdale 20738 | (301) 699-9500 |
| National Trust-The Development 6811 Kenilworth Ave # 501, Riverdale 20737 | (301) 887-0100 |
| Sampson High School Alumni Po Box 975, Riverdale 20738 | (301) 552-4507 |
| Biotechnology Permit Unit 147 4700 River Rd # 147, Riverdale 20737 | (301) 734-5140 |
| Columbia Lighthouse-The Blind 6200 Baltimore Ave # 100, Riverdale 20737 | (240) 737-5100 |