Department of Defense NAICS 561621 contractors

Security Systems Services (except Locksmiths). Contractors in this NAICS lane under Department of Defense.

Agency: Department of Defense

Last updated: April 17, 2026

Visible recipients

Mapped obligations

$2,292,847,952

Visible recipients tied to Department of Defense and NAICS 561621

Serco INC

Herndon, VA

Herndon, VA | 1,016 awards | Top agency Department of Defense | NAICS 541330

$653,436,871

Paragon Systems INC

Herndon, VA

Herndon, VA | 691 awards | Top agency Department of Homeland Security | NAICS 561612

$257,864,029

Triple Canopy INC

Herndon, VA

Herndon, VA | 326 awards | Top agency Department of State | NAICS 561612

$244,892,339

M. C. Dean, Inc.

Tysons, VA

Tysons, VA | 1,299 awards | Top agency Department of Defense | NAICS 541330

$721,375,070

Centerra Group, LLC

Herndon, VA

Herndon, VA | 143 awards | Top agency Department of Energy | NAICS 561612

$41,449,827

Johnson Controls Building Automation Systems, LLC

Huntsville, AL

Huntsville, AL | 154 awards | Top agency Department of Defense | NAICS 541512

$101,336,050

Alutiiq Global Solutions, LLC

Anchorage, AK

Anchorage, AK | 5 awards | Top agency Department of Defense | NAICS 236220

$26,014,603

Chenega Global Protection, LLC

Chantilly, VA

Chantilly, VA | 371 awards | Top agency National Aeronautics and Space Administration | NAICS 561612

$29,577,490

Siemens Government Technologies INC

Arlington, VA

Arlington, VA | 227 awards | Top agency Department of Defense | NAICS 541512

$57,176,178

Caddell Construction Co. (de), LLC

Montgomery, AL

Montgomery, AL | 67 awards | Top agency Department of State | NAICS 236220

$74,267

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