The number of undocumented immigrants arrested by U.S. Immigration and Customs Enforcement dropped 23 percent nationwide between Sept. 30, 2012, and August 2013, though it increased in a half-dozen cities, according to Homeland Security figures.
The monthly average of undocumented immigrants arrested shot up by 78 percent in Buffalo, New York.
At the same time it rose in Philadelphia by 10 percent, in New Orleans by 7 percent, in Detroit by 6 percent, and in Saint Paul, Minnesota, by 5 percent.
The cities that showed the greatest decline in arrests of the undocumented were Miami, San Diego, Atlanta, Houston and Chicago, according to ICE data published by the Transactional Records Access Clearinghouse based at Syracuse University.
The ICE office in Miami prosecuted 33 percent fewer persons than it did the year before.
Nationwide, a monthly average of 17,691 undocumented immigrants were arrested last year, compared with 22,832 in 2012.
Detention centers with the biggest increase in the number of undocumented persons confined per month were those in the District of Colombia with a 64 percent increase, North Dakota with 26 percent, Alaska with 19 percent, New York with 10 percent, and Pennsylvania with an increase of 8 percent.
In his annual report, ICE Director John Sandweg said that in fiscal year 2013, which ended Sept. 30, the nation deported 368,644 undocumented immigrants.
That number is lower than the average of 30,941 for the three previous fiscal years.