Many states have experienced a large influx of undocumented migrants in recent years. It has resulted in contentious debates regarding the burdens and benefits of their presence in the U.S. and in individual states and the need for comprehensive immigration reform. This research examines factors that influence the location decisions of undocumented migrants in the U.S. Greater economic opportunities, the existence of migrant networks, and the share of agriculture, accommodation, and food services sectors in the Gross State Product have a posi-tive and significant impact on percentage of undocumented migrants at the state level. Un-documented migrants also appear to locate in states with policies that foster greater individual freedoms. The evidence of clustering of undocumented migrants in states with large migrant networks could pose challenges for states trying to regulate the size of their undocumented migrant population.