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Mason & Hanger®, a Day & Zimmermann company, is dedicated to providing architectural and engineering (A/E) services specializing in the worldwide design of secure, mission-driven facilities.

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For nearly two centuries, Mason & Hanger has been a trusted partner of the U.S. Department of Defense (Army, Navy, Air Force, Marines, National Guard – active and reserves), Department of Homeland Security, Department of State, Department of Energy, as well as NASA, and other government agencies critical to the U.S. National Security Mission. Mason & Hanger has provided best-in-class architectural and engineering (A/E) services to the federal government on thousands of projects in more than 170 countries. Mason & Hanger has ranked nationally among the Top 15 A/E firms in Government Building Design.


History of Operating in Support of the U.S. Government


Years (in 2027) as the longest operating American A/E Firm supporting the U.S. Federal Government


Years Supporting the Department of Energy at Category I Special Nuclear Material research, development, and manufacturing environments


Years supporting Department of Defense, facility design and maintenance, demilitarization operations and research and development

TOP 100

Defense Company, rated by Bloomberg Government and Defense News

Ben Lilly headshot "We provide smart, innovative solutions for difficult and complex design challenges to support the U.S. Government with their security missions globally."
-Benjamin A. Lilly, President, Mason & Hanger


Learn more about Mason & Hanger's culture here.

Our Culture

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At Mason & Hanger, we provide the opportunity to join a successful team of innovative thinkers, including many of the industry’s most talented individuals. Our mission of building a more secure world has a direct impact when it comes to protecting U.S. national security interests at home and abroad. With a foundation built on our values of Safety, Integrity, Diversity and Success, we're committed to creating an inclusive and team-oriented environment, offering some of the most competitive benefits, and talent development through training and growth opportunities.

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Dive Into Our Video Series: Perspectives on U.S. National Security

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Check Out Our Munitions Modernization Video Series 

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Hear from Our Veterans