The backlog of pending deportation cases in US immigration courts has risen to nearly 400,000 amid a crush of tens of thousands of unaccompanied children and families caught crossing the Mexican border illegally this year, according an analysis of court data released Friday.

The Transactional Records Access Clearinghouse at Syracuse University said in its latest report that as of the end of July, 396,552 cases were pending in the Justice Department’s 59 immigration courts. TRAC collects and studies a variety of federal prosecution records.

The backlog has grown by more than 75,000 cases since the start of the budget year in October, according to TRAC.

The Executive Office for Immigration Review, the Justice Department agency that operates immigration courts, said Friday its records show a caseload of 391,243 pending cases as of 31 July. An agency spokeswoman said the methodology TRAC uses to analyze court data may be different than the methods used by the government.

Since 1 October the Homeland Security Department has reported that more than 66,000 unaccompanied child immigrants, mostly from Honduras, El Salvador and Guatemala, have been caught crossing the Mexican border illegally. More than 66,000 additional immigrants traveling as families, mostly mothers and young children from Central America, have also been caught.

Homeland Security Secretary Jeh Johnson has said that all of the immigrants caught crossing the border would face deportation hearings.

The TRAC report shows that the largest backlogs are in immigration courts in California, Texas and New York.

The large and growing court backlog has led to years-long waits for immigration cases to be completed. Earlier this year, the Justice Department announced plans to move cases of unaccompanied immigrant children to the top of the docket.