The following map shows an estimated percentage of federal immigration cases per unauthorized immigrant for each state. It uses research from the Pew Research Center on estimated state unauthorized immigrant populations in 2012, and data from the U.S. Sentencing Commission for federal immigration offenses that same year.
I excluded five states—Maine, the Dakotas, Vermont, and Montana—because Pew could only determine that the unauthorized immigrant population in those states was less than 5,000, and the imprecision at those low value threw off the calculations.
Some interesting things to note: New Mexico had the highest level of federal prosecutions per unauthorized immigrant. The state’s 2012 unauthorized immigrant population was estimated at 70,000, and there were 2,097 federal immigration cases, for a rough estimate of nearly 3% of the unauthorized immigrants being prosecuted. In contrast, federal officials in New Jersey, which had a 2012 authorized immigrant population of around 525,000, prosecuted only 45 immigration cases that year (not even .01%). The average percentage was .24.
The “why” for these statistics is not cut and dry. It could be that immigration officials conduct more aggressive enforcement in some states. Or that federal prosecutors prosecute more of the offense brought to them. Or that there is some reason unauthorized immigrants are staying under the radar in certain places.
Here is a link to download an excel file with the statistics.