This paper reports the results of fitting migration rules based on gravity models and the theory of intervening opportunities to the “flow” of crimes among urban locations. Crime, like other phenomena of demographic flow, is shown to be subject to the general class of inverse distance variations formulated as gravity laws. While the theory of intervening opportunities fares poorly in comparison to models incorporating a measure of distance, the best fit achieved empirically is based on a composite gravity rule that includes a term roughly equivalent to Stouffer's concept of opportunities. A separate analysis of the flow of property crimes failed to improve the fit of models otherwise successful in predicting the flow of all crimes.