The southwestern States that share a border with Mexico–Texas, New Mexico, Arizona, and California -- are put under strain when they must process illegal immigrants caught with illegal drugs. Illegal immigrants arrested for drug smuggling are not deported, rather they are processed through the local criminal justice system. They are also rarely transferred to the Federal justice system because most are caught with amounts of illegal drugs that are below the unofficial threshold for Federal involvement. Once in custody, local tax money must pay for any medical services, autopsies, or burials that are necessary in the care of the illegal immigrant. As such, border States are under increasing financial strain to support the influx of illegal immigrants that must be processed through the criminal justice system. This study examined two research questions: (1) How does providing law enforcement, criminal justice, and emergency medical services to illegal immigrants affect the workload of each county department in the border States, and (2) what are the financial costs? Site visits were conducted in each county between February 2000 and December 2000. Interviews were conducted with key stakeholders and documents concerning county budgets, U.S. Census data, INS border crossing data, Border Patrol apprehension data, newspaper accounts, public documents, and public testimony in congressional hearings were analyzed. Results indicated that the total cost to border counties was approximately $108.2 million in fiscal year 1999. The two California counties carried most of the cost, over 50 percent of the total; however, when measured on a per capita basis, the smallest and poorest counties had the highest financial burden. Over half of New Mexico’s public safety budget in 1999 was spent on criminal illegal immigrants. Emergency medical services cost the 24 counties $19.1 million in fiscal year 1999. Findings should assist lawmakers in designing legislation that would shift the costs of criminal illegal immigrants from the county governments to the Federal Government.