Counties Shared Between IHS Areas or Partially Contained Within an IHS Area— 2003 Percentage Splits
| State and County | IHS Area | Percentage of County’s AI/AN Population Assigned to IHS Area | ||
| Arizona | Apache County | Navajo | 98.747 | |
| Phoenix | 1.253 | |||
| Coconino County | Navajo | 97.404 | ||
| Phoenix | 2.596 | |||
| Maricopa County | Phoenix | 99.73 | ||
| Tucson | 0.27 | |||
| Navajo County | Navajo | 62.014 | ||
| Phoenix | 37.986 | |||
| Pinal County | Phoenix | 93.371 | ||
| Tucson | 6.629 | |||
| California | Fresno County | California | 47.62 | |
| Non-Service Area | 52.38 | |||
| Imperial County | Phoenix | 92.577 | ||
| California | 7.423 | |||
| Riverside County | California | 99.243 | ||
| Phoenix | 0.757 | |||
| San Bernardino County | California | 95.668 | ||
| Phoenix | 4.332 | |||
| San Diego County | California | 76 | ||
| Non-Service Area | 24 | |||
| Santa Barbara County | California | 23.999 | ||
| Non-Service Area | 76.001 | |||
| New Mexico | Cibola County | Albuquerque | 98.667 | |
| Navajo | 1.333 | |||
| McKinley County | Navajo | 83.562 | ||
| Albuquerque | 16.438 | |||
| Rio Arriba County | Albuquerque | 98.679 | ||
| Navajo | 1.321 | |||
| Sandoval County | Albuquerque | 77.624 | ||
| Navajo | 22.376 | |||
| Utah | Kane County | Phoenix | 62.338 | |
| Navajo | 37.662 | |||
| San Juan County | Navajo | 96.428 | ||
| Albuquerque | 3.572 | |||
Source: IHS Division of Program Statistics Appendix B