Company lists · Data refreshed September 2026

Top 25 Critical infrastructure defense based in the United States

RevenueBase identified 5,633 critical infrastructure defense headquartered in the United States as of September 2026 and tracks 320,288 professional contacts across them, including 72,763 with verified work emails. New York is the largest hub.

This list covers critical infrastructure defense headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 16, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 16, 2026 86% judged on-target in blind review
5,633Companies
320,288Contacts tracked
72,763Verified emails
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The 25 largest critical infrastructure defense based in the United States

Ranked by team size
Top 25 of 5,633 critical infrastructure defense based in the United States, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to critical infrastructure defense: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceIrvine, CA, United StatesHQ checked Sep 16, 202610001+62,804 contacts →

Indirect evidence

“Allied Universal®, a leading security and facility services company, provides proactive security services and cutting-edge smart technology to deliver evolving, tailored solutions…”

Source: RevenueBase Database · checked Sep 16, 2026
2Indirect evidenceParsippany, NJ, United StatesHQ checked Sep 16, 202610001+38,634 contacts →

Indirect evidence

“Securitas knows Security.”

Source: RevenueBase Database · checked Sep 16, 2026
3Indirect evidenceSanta Clara, CA, United StatesHQ checked Sep 16, 202610001+18,431 contacts →

Indirect evidence

“Palo Alto Networks, the global cybersecurity leader, is shaping the cloud-centric future with technology that is transforming the way people and organizations operate.”

Source: RevenueBase Database · checked Sep 16, 2026
4Indirect evidenceSunnyvale, CA, United StatesHQ checked Sep 16, 202610001+14,289 contacts →

Indirect evidence

“Fortinet makes possible a digital world that we can always trust through its mission to protect people, devices, and data everywhere.”

Source: RevenueBase Database · checked Sep 16, 2026
5Indirect evidenceSan Jose, CA, United StatesHQ checked Sep 16, 202610001+11,169 contacts →

Indirect evidence

“Your backstage pass to the most epic cybersecurity solutions on the market for Endpoint, Network, Data and Cloud security.”

Source: RevenueBase Database · checked Sep 16, 2026
6Indirect evidenceReston, VA, United StatesHQ checked Sep 16, 202610001+10,793 contacts →

Indirect evidence

“At Peraton, we're at the forefront of delivering the next big thing every day.”

Source: RevenueBase Database · checked Sep 16, 2026
7Indirect evidenceHerndon, VA, United StatesHQ checked Sep 16, 20265,001-10,0009,697 contacts →

Indirect evidence

“MANTECH is more than a technology company.”

Source: RevenueBase Database · checked Sep 16, 2026
8Indirect evidenceHoffman Estates, IL, United StatesHQ checked Sep 16, 202610001+5,707 contacts →

Indirect evidence

“Convergint is a global systems integrator focused on delivering results for our customers through unparalleled service excellence.”

Source: RevenueBase Database · checked Sep 16, 2026
9Partial evidenceSt. Petersburg, FL, United StatesHQ checked Sep 16, 2026n/a4,038 contacts →

Partial evidence

“Excelsior Defense is a security and investigations company based out of St.”

Source: RevenueBase Database · checked Sep 16, 2026
10Indirect evidenceRoswell, GA, United StatesHQ checked Sep 16, 202610001+3,592 contacts →

Indirect evidence

“U.S.”

Source: RevenueBase Database · checked Sep 16, 2026
11Indirect evidenceAurora, IL, United StatesHQ checked Sep 16, 20265,001-10,0002,266 contacts →

Indirect evidence

“Andy Frain Services.America's leading provider of integrated solutions to security and events needs for over 90 years.”

Source: RevenueBase Database · checked Sep 16, 2026
12Indirect evidenceLeawood, KS, United StatesHQ checked Sep 16, 20261,001-5,0002,222 contacts →

Indirect evidence

“Optiv is the cyber advisory and solutions leader, delivering strategic and technical expertise to nearly companies across every major industry.”

Source: RevenueBase Database · checked Sep 16, 2026
13Indirect evidenceAnnapolis, MD, United StatesHQ checked Sep 16, 20261,001-5,0002,025 contacts →

Indirect evidence

“Crisis24, a GardaWorld company, is widely regarded as the leading integrated risk management, crisis response, consulting, and global protective solutions firm, serving the…”

Source: RevenueBase Database · checked Sep 16, 2026
14Indirect evidenceAnn Arbor, MI, United StatesHQ checked Sep 16, 20261,001-5,0002,022 contacts →

Indirect evidence

“Pinkerton, established in 1850 by Allan Pinkerton, stands as a leading global provider of security and risk management solutions.”

Source: RevenueBase Database · checked Sep 16, 2026
15Indirect evidenceHerndon, VA, United StatesHQ checked Sep 16, 202610001+1,949 contacts →

Indirect evidence

“Paragon Systems employs over 10,500 professionals in specialized operations providing security, fire, investigations, inspections, cybersecurity, risk management, and mission…”

Source: RevenueBase Database · checked Sep 16, 2026
16Indirect evidenceDenver, CO, United StatesHQ checked Sep 16, 20265,001-10,0001,727 contacts →

Indirect evidence

“HSS is now Tarian!”

Source: RevenueBase Database · checked Sep 16, 2026
17Strong evidenceHuntsville, AL, United StatesHQ checked Sep 16, 202610001+1,532 contacts →

Strong evidence

“Leidos Dynetics provides responsive, cost-effective engineering, scientific, IT solutions to the national security, cybersecurity, space, and critical infrastructure sectors.”

Source: RevenueBase Database · checked Sep 16, 2026
18Indirect evidenceRomeoville, IL, United StatesHQ checked Sep 16, 20261,001-5,0001,406 contacts →

Indirect evidence

“As of May 2016, Protection 1 and ADT merged together to become the leading company in the electronic security industry.”

Source: RevenueBase Database · checked Sep 16, 2026
19Indirect evidenceNew Orleans, LA, United StatesHQ checked Sep 16, 20261,001-5,0001,399 contacts →

Indirect evidence

“Weiser Security Services is the 11th largest security service provider in the U.S.”

Source: RevenueBase Database · checked Sep 16, 2026
20Indirect evidenceNew York, NY, United StatesHQ checked Sep 16, 202610001+1,375 contacts →

Indirect evidence

“Guardsmark, LLC provides security services.”

Source: RevenueBase Database · checked Sep 16, 2026
21Partial evidenceAustin, TX, United StatesHQ checked Sep 16, 20261,001-5,0001,252 contacts →

Partial evidence

“Thales is a global leader in cybersecurity, helping the most trusted organizations in the world protect their most critical applications, data, and identities anywhere at scale.”

Source: RevenueBase Database · checked Sep 16, 2026
22Indirect evidenceReston, VA, United StatesHQ checked Sep 16, 20261,001-5,0001,232 contacts →

Indirect evidence

“GuidePoint Security provides trusted cybersecurity expertise, solutions, and services that help organizations make informed decisions and minimize risk.”

Source: RevenueBase Database · checked Sep 16, 2026
23Indirect evidenceAustin, TX, United StatesHQ checked Sep 16, 202610001+1,217 contacts →

Indirect evidence

“On Dec.”

Source: RevenueBase Database · checked Sep 16, 2026
24Indirect evidenceMorrisville, NC, United StatesHQ checked Sep 16, 2026501-1,0001,175 contacts →

Indirect evidence

“IEM is a professional services firm dedicated to building a safe, secure, and resilient world.”

Source: RevenueBase Database · checked Sep 16, 2026
25Indirect evidenceParsippany, NJ, United StatesHQ checked Sep 16, 202610001+1,151 contacts →

Indirect evidence

“SOS Security is a known innovator and leader in the security and protective services industry.”

Source: RevenueBase Database · checked Sep 16, 2026

Showing 25 of 5,633 critical infrastructure defense based in the United States

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Critical infrastructure defense based in the United States at a glance

As of Sep 16, 2026
22.7%Verified-email coverage
56.9Average contacts per company
11-50Median size (employees)
2.6%Largest-city concentration · New York
Sep 16, 2026Page data refreshed

Companies by employee count

1-10
2,620
11-50
1,855
51-200
755
201-500
187
501-1,000
90
1,001-5,000
76
5,001-10,000
15
10001+
25

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 5,633 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among critical infrastructure defense, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “critical infrastructure defense”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names critical infrastructure defense), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among critical infrastructure defense, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 72,763 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 16, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Critical infrastructure defense by metro

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names critical infrastructure defense, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many critical infrastructure defense are there based in the United States?

RevenueBase identified 5,633 critical infrastructure defense headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Allied Universal, headquartered in Irvine, tops this list with the largest team on record.

Which city has the most critical infrastructure defense?

New York leads with 144 headquartered companies, followed by Houston (121) and Washington (103).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 72,763 verified decision-maker contacts tracked across these 5,633 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 16, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.