Buprenorphine, an effective treatment for opioid use disorder (OUD), remains underutilized in many U.S. jails and prisons. However, use of non-prescribed (i.e., diverted) buprenorphine has been reported in these settings. The current study examined non-prescribed buprenorphine use experiences in correctional and community contexts. The study conducted face-to-face interviews with 300 adults with OUD/opioid misuse and recent incarceration, recruited in Baltimore, MD, and New York, NY (n = 150 each). Illicit/non-prescribed opioid use during incarceration was reported by 63% of participants; 39% reported non-prescribed buprenorphine. Non--prescribed buprenorphine was considered the most widely available opioid in jails/prisons in both states (81% reported "very" or "somewhat" easy to get). The average price of non-prescribed buprenorphine in jail/prison was ~10× higher than in the community (p < 0.001). Participants were more likely to endorse getting high/ mood alteration as reasons for using non-prescribed buprenorphine during incarceration, but tended to ascribe therapeutic motives to use in the community (e.g., self-treatment; p < 0.001). Multivariable logistic regression analyses showed that different individual-level characteristics were associated with history of non-prescribed buprenorphine use during incarceration and in the community. Use of non-prescribed buprenorphine during incarceration was associated with younger age (p = 0.006) and longer incarceration history (p < 0.001), while use of non-prescribed buprenorphine in the community was associated with MD recruitment site (p = 0.001), not being married (p < 0.001), prior buprenorphine treatment experience (p < 0.001), and housing situation (p = 0.01). These findings suggest that different dynamics and demand characteristics underlie the use of non--prescribed buprenorphine in community and incarceration contexts, with implications for efforts to expand OUD treatment in correctional settings.