The Cybersecurity and Infrastructure Security Agency (CISA) leads the national effort to understand, manage, and reduce risk to our cyber and physical infrastructure. We connect our stakeholders in industry and government to each other and to resources, analyses, and tools to help them build their own cyber, communications, and physical security and resilience, in turn helping to ensure a secure and resilient infrastructure for the American people. Our 2021 Year in Review displays key examples of CISA’s work to carry out its mission in 2021, including milestones and accomplishments as the Agency advanced strategic priorities to maintain a secure and resilient infrastructure for the nation.