The social dynamics of some communities are affected by the loss of significant numbers of people to prison and by the release of others who encounter the challenge of coping with the negative effects of the incarceration experience. The effects on communities are evident, in part, in the high rates of sexually transmitted infections (STIs) in North Carolina (NC) counties that have a high rate of incarceration. In the present study, we examined whether the same associations can be observed at the census tract level in one urban city of NC. To identify the mechanisms by which incarceration can affect the transmission of STIs, we conducted ethnographic interviews with ex-offenders and people who lost a sexual partner to prison. We found that census tract rates of incarceration were consistently associated with gonorrhea rates in the subsequent year. An increase of the percentage of census tract person-time spent in prison from 2.0% to 2.5% corresponded to a gonorrhea rate increase of 7.1 cases per 100,000 person-years. The people interviewed spoke of sexual partnership changes including those left behind finding new partners, in part for help in making financial ends meet; men having sex with men for the first time in prison; and having multiple new partners upon reentry to the community. The statistical associations and stories of the effects of incarceration on sexual relationships provide additional evidence of unintended community health consequences of high rates of incarceration.