Continuity of government (COG) is the principle of establishing defined procedures that allow a government to continue its essential operations in case of a catastrophic event such as nuclear war.

Continuity of Operations (COOP) is a United States federal government initiative, required by U.S. Presidential Policy Directive 40 (PPD-40), to ensure that agencies are able to continue performance of essential functions under a broad range of circumstances. PPD-40 specifies certain requirements for continuity plan development, including the requirement that all federal executive branch departments and agencies develop an integrated, overlapping continuity capability, that supports the eight National Essential Functions (NEFs) described in the document.