In the 1990s, the U.S. border led the nation in the decline of property-related crimes, while violent crime rates fell twice as fast in the U.S. as in the median border county. This paper asks how changes in undocumented immigration and border enforcement have played a role in generating these divergent trends. We find that migrant apprehensions are correlated with violent crime and that increased border enforcement has not had a deterrent effect on such crime. Rather, increased border enforcement in a sector has led to more violent crime in neighboring sectors. In contrast to the results for violent crime, property crime is not correlated with migrant apprehensions, and while there is some evidence that border enforcement has lowered property crime rates, this result is sensitive to the model's specification. Our findings also indicate that the improved border economy over this period, specifically rapid job growth, played a significant role in lowering property crime rates. [ABSTRACT FROM AUTHOR]