According to 2016 data from the World Prison Brief, released by the Institute for Criminal Policy Research, the United States has the highest national rate of imprisonment: 655 jailed persons per 100,000 of the national population. Canada and Mexico have rates of 114 and 164, respectively. The United States houses over 2 million inmates in 4,455 facilities that may fall under local, state or federal jurisdiction. Inmates are a huge sector of the American population. They’re a group that may not come to mind when thinking about our country’s most vulnerable populations, yet they face significant barriers to accessing adequate health care.