US Homeland Security Secretary Janet Napolitano is to step down to become the next president of the University of California.
The Department of Homeland Security was created in response to the 9/11 attacks. It includes 22 departments.
The department's mandate ranges from immigration and deportations to airport screenings to disaster management.
Ms Napolitano will leave the department in early September. The announcement was made on Friday.
The BBC reports she presided over changes to immigration enforcement and a new focus on disaster response during her tenure.
The former Arizona governor had been an outspoken advocate for changing the US immigration laws.
Ms Napolitano has been praised for restoring the Federal Emergency Management Agency to good standing after its response to Hurricane Katrina in 2005.
But others said she was not strong enough on deportations and on US border security.