ABC News reports on some of the ways sequestration will impact the immigration system.

According to Attorney General Holder:

"The sequestration would cut over $15 million from [the Executive Office
for Immigration Review] EOIR's current budget. EOIR would be forced to
cease all hiring of key critical positions for EOIR's immigration
courts, including Immigration Judges, likely increasing pending
caseloads to well over 350,000 (an increase of 6 percent over September
2012 levels." EOIR would also cut contracts for interpreters, legal
support, and I.T. staff."

Regarding passports and visa processing, Secretary Kerry had this prediction:

"Reductions in funding would jeopardize the
Department's efforts to provide secure, error-free travel documents to
those eligible to receive them, while denying them to those not
eligible. Reduced funding would also undermine progress made in ensuring
that visa requests are processed in a timely fashion."

Elise Foley at Huffington Post reports on the impact of sequestration at ICE where cuts are already being implemented:

Immigration and Customs Enforcement released some people from immigrant detention facilities across the country on Monday in response to looming federal budget cuts.

"In order to make the best use of our limited detention resources in the current fiscal climate and to manage our detention population under current congressionally mandated levels, ICE has directed field offices to review the detained population to ensure it is in line with available funding," agency spokeswoman Gillian Christensen said in a statement.

USCIS might be a little less vulnerable to the cuts since much of its funding comes from fees rather than appropriations.