The emergency contraceptive pill Plan B, which can prevent pregnancy following unprotected sex, has been available over the counter at most American pharmacies for more than a decade. But in more than 100 federally funded clinics and pharmacies run by or on behalf of Native American tribal nations, the medication is harder to access — if it’s available at all.

An investigation by APM Reports, Type Investigations and KOSU found 54 tribal clinics spread across 11 states that do not provide emergency contraception. They were in Alaska, Arizona, California, Florida, Louisiana, Michigan, Minnesota, Montana, Nebraska, Oklahoma and Washington. Another 51 clinics impose limits on access — things such as age restrictions or needing to see a nurse or doctor first. Collectively, these clinics serve tens of thousands of women.