A new study of criminal case activity in the federal courts since October 2006 shows that judicial caseloads varied widely not only between courts in different districts, but also among judges serving in the same court.

The Transactional Records Access Clearinghouse, or TRAC, which is based at Syracuse University, released the results of its latest study of judicial activity on November 12. Average judicial caseloads, as measured by the number of defendants sentenced per judge, ranged from a high of 7,020 in the Las Cruces federal court in New Mexico to a low of 147 in the District of Columbia.

TRAC Co-Director Susan Long said today that she and other researchers were surprised by the wide range of criminal caseloads across the country and within courthouses. She said the data did back up anecdotal reports that criminal caseloads have tended to be higher in states along the U.S.-Mexico border; the 10 courts with the largest average criminal caseloads were in New Mexico, Texas, Arizona and California.

According to the report, Southwestern border states had the highest number of sentencings because of the federal government’s “sharply increased” criminal enforcement of immigration matters.

Besides the District of Columbia, courts with the smallest average criminal caseloads included the Central Islip, N.Y., courthouse of the Eastern District of New York and the Camden, N.J., courthouse.

The study tracked the number of sentencings in front of 430 federal judges who were active between October 2006 and July 2012. A spokesman for the Administrative Office of the U.S. Courts could not be reached today for comment. Federal courts were closed Monday in observance of Veteran’s Day.

Criminal caseloads varied the most among judges serving in the Central District of California’s Los Angeles courthouse. The number of sentencings before the 13 active judges studied from that court ranged from a high of 305 to a low of 134. The difference in caseloads was similarly high among the two judges studied from the Beaumont, Texas courthouse of the Eastern District of Texas and the four judges studied within Camden, N.J., courthouse.

Caseloads varied least among the two active judges in the Brownsville, Texas courthouse of the Southern District of Texas – the judges there handled 3,866 and 3,877 sentencings, respectively. The difference in caseloads was similarly low among the three judges studied from the El Paso, Texas courthouse of the Western District of Texas and the two judges studied from the Providence, R.I., courthouse.

Long said that while not all criminal cases end in a conviction, either because a case was dismissed or the defendant was acquitted, the majority of cases end in guilty pleas or jury verdicts, so they decided that sentencings were an accurate way to gauge total caseloads. “This seemed to be a more stable universe and more comparable,” she said.

TRAC also broke down the total number of convictions for all 430 judges who were active during the study period. U.S. District Judge Robert Brack was the only active judge studied from the Las Cruces court in New Mexico, putting him far ahead of his colleagues with 7,020 defendants sentenced during the study period. U.S. District Judge Micaela Alvarez of the Southern District of Texas came in second with 6,350 sentencings. She was one of three active judges studied who serve in the McAllen, Texas courthouse.

U.S. District Judge Renee Bumb, who serves in the Camden, N.J., courthouse, handled the lowest number of sentencings during the study period, according to TRAC; she sentenced 119 defendants. Her chambers could not be reached, but the Associated Press reported that the chief judge of the U.S. District Court of New Jersey said that Bumb was one of two judges who joined the court in 2006 and did not handle many criminal cases early on because they had previously served as prosecutors.

Zoe Tillman is a reporter for The National Law Journal, a Legal affiliate based in New York.