| Abbreviation | Definition |
|---|---|
| HCLS | Henry County Library System |
| HCLS | Hidalgo County Library System |
| HCLS | Howard County Library System |
| HCPL | Hancock County Public Library |
| HCPL | Hardin County Public Library |
| HCPL | Harford County Public Library |
| HCPL | Harris County Public Library |
| HCPL | Harrison County Public Library |
| HCPL | Henderson County Public Library |
| HCPL | Humphreys County Public Library |
| HCPLS | Hernando County Public Library System |
| HCPLS | Houston County Public Library System |
| HCTL | Hills Community Toy Library |
| HDC | Harvard Depository Collection |
| HEAL | Health Education Assets Library |
| HELIN | Higher Education Library Information Network |
| HEPL | Hamilton East Public Library |
| HGL | Harvard Geospatial Library |
| HHSL | Harrell Health Sciences Library |
| HHSL | Highland Health Sciences Library |