The report by the Migration Policy Institute said the $18 billion spent enforcing immigration laws last year was approximately 24 percent higher than the combined spending on the FBI, Drug Enforcement Administration, Secret Service, U.S. Marshals Service and Bureau of Alcohol, Tobacco, Firearms and Explosives.
Since passage of the Immigration Reform and Control Act in 1986, the United States has spent nearly $187 billion on immigration enforcement, the report said.
"Today, immigration enforcement can be seen as the federal government's highest criminal law enforcement priority, judged on the basis of budget allocations, enforcement actions and case volumes," said Doris Meissner, co-author of the report, in a release.
The 182-page report said the nation's main immigration enforcement agencies refer more cases for federal prosecutions than all Justice Department law enforcement agencies.
The Migration Policy Institute is an independent, non-partisan, non-profit think tank in Washington dedicated to the study of the movement of people worldwide.