Drugs, crime, and public housing are closely linked in policy and politics, and their nexus has animated several intensive drug enforcement programs targeted at public housing residents. In New York City, police systematically conduct “vertical patrols” in public housing buildings, making tens of thousands of Terry stops each year. During these patrols, both uniformed and undercover officers systematically move through the buildings, temporarily detaining and questioning residents and visitors, often at a low threshold of suspicion, and usually alleging trespass to justify the stop. We use a case-control design to identify the effects of living in one of New York City's 330 public housing developments on the probability of stop, frisk, and arrest from 2004–2011. We find that the incidence rate ratio for trespass stops and arrests is more than two times greater in public housing than in the immediate surrounding neighborhoods. We decompose these effects using first differences models and find that the difference in percent black and Hispanic populations in public housing compared to the surrounding area predicts the disparity in trespass enforcement and enforcement of other criminal law violations. The pattern of racially selective enforcement suggests the potential for systemic violations of the Fourteenth Amendment's prohibition on racial discrimination.