Company lists · Data refreshed September 2026

Top 25 Security firms based in the United States

RevenueBase identified 6,852 security firms headquartered in the United States as of September 2026 and tracks 274,843 professional contacts across them, including 29,678 with verified work emails and 86,813 with mobile numbers. New York is the largest hub.

This list covers security firms 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 6, 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 6, 2026 86% judged on-target in blind review
6,852Companies
274,843Contacts tracked
29,678Verified emails
86,813Mobile numbers
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The 25 largest security firms based in the United States

Ranked by team size
Top 25 of 6,852 security firms based in the United States, ranked by team size, largest first. Data refreshed Sep 6, 2026. RevenueBase Smart Search rates how each company's information relates to security firms: 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
1Strong evidenceIrvine, CA, United StatesHQ checked Sep 6, 202610001+62,804 contacts →

Strong 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 6, 2026
2Strong evidenceParsippany, NJ, United StatesHQ checked Sep 6, 202610001+38,634 contacts →

Strong evidence

“Securitas knows Security.”

Source: RevenueBase Database · checked Sep 6, 2026
3Strong evidenceSt. Petersburg, FL, United StatesHQ checked Sep 6, 2026n/a4,038 contacts →

Strong evidence

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

Source: RevenueBase Database · checked Sep 6, 2026
4Indirect evidenceNorthridge, CA, United StatesHQ checked Sep 6, 202610001+4,025 contacts →

Indirect evidence

“Contemporary Services Corporation (CSC) is recognized worldwide as the pioneer, expert and only employee owned company in the crowd management field.”

Source: RevenueBase Database · checked Sep 6, 2026
5Strong evidencePasadena, CA, United StatesHQ checked Sep 6, 202610001+3,612 contacts →

Strong evidence

“EVERYWHERE SECURITY MATTERS.”

Source: RevenueBase Database · checked Sep 6, 2026
6Indirect evidenceRoswell, GA, United StatesHQ checked Sep 6, 202610001+3,592 contacts →

Indirect evidence

“U.S.”

Source: RevenueBase Database · checked Sep 6, 2026
7Strong evidenceCulver City, CA, United StatesHQ checked Sep 6, 20265,001-10,0002,500 contacts →

Strong evidence

“The industry leader in security, Security Industry Specialists offers unique solutions to Fortune 500 companies, international events, and celebrity clients.”

Source: RevenueBase Database · checked Sep 6, 2026
8Strong evidenceAurora, IL, United StatesHQ checked Sep 6, 20265,001-10,0002,266 contacts →

Strong 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 6, 2026
9Strong evidenceChattanooga, TN, United StatesHQ checked Sep 6, 20265,001-10,0002,174 contacts →

Strong evidence

“Through an ISO® 9001:2015 Certified Quality Management System (QMS), Walden Security has earned an award-winning reputation for business excellence and employee satisfaction…”

Source: RevenueBase Database · checked Sep 6, 2026
10Strong evidenceIrving, TX, United StatesHQ checked Sep 6, 20261,001-5,0002,045 contacts →

Strong evidence

“Everon is a leading national provider of commercial security, video, fire, sprinkler, and life safety solutions for complex, multi-site businesses and organizations.”

Source: RevenueBase Database · checked Sep 6, 2026
11Strong evidenceHerndon, VA, United StatesHQ checked Sep 6, 202610001+1,949 contacts →

Strong 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 6, 2026
12Indirect evidenceSt. Louis, MO, United StatesHQ checked Sep 6, 20265,001-10,0001,781 contacts →

Indirect evidence

“Whelan’s commitment to quality and service has made us one of the foremost respected, successful and fastest growing companies in the industry.”

Source: RevenueBase Database · checked Sep 6, 2026
13Indirect evidenceDenver, CO, United StatesHQ checked Sep 6, 20265,001-10,0001,727 contacts →

Indirect evidence

“HSS is now Tarian!”

Source: RevenueBase Database · checked Sep 6, 2026
14Strong evidenceRaleigh, NC, United StatesHQ checked Sep 6, 20265,001-10,0001,639 contacts →

Strong evidence

“Sunstates Security, LLC is one of the industry's leading providers of contract security services with a differentiated approach to providing successful, cost-effective, quality…”

Source: RevenueBase Database · checked Sep 6, 2026
15Strong evidenceStaten Island, NY, United StatesHQ checked Sep 6, 20265,001-10,0001,497 contacts →

Strong evidence

“Since 1994, Metro One has grown from a local, guard-based security firm into a nationally recognized leader in retail loss prevention-trusted by 8 of the Top 10 U.S.”

Source: RevenueBase Database · checked Sep 6, 2026
16Strong evidenceBethesda, MD, United StatesHQ checked Sep 6, 20265,001-10,0001,441 contacts →

Strong evidence

“Admiral Security Services provides professional armed and unarmed uniformed security officers, unparalleled site management and unwavering corporate support that exceeds client…”

Source: RevenueBase Database · checked Sep 6, 2026
17Strong evidenceRomeoville, IL, United StatesHQ checked Sep 6, 20261,001-5,0001,406 contacts →

Strong 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 6, 2026
18Strong evidenceNew Orleans, LA, United StatesHQ checked Sep 6, 20261,001-5,0001,399 contacts →

Strong evidence

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

Source: RevenueBase Database · checked Sep 6, 2026
19Strong evidenceNew York, NY, United StatesHQ checked Sep 6, 202610001+1,375 contacts →

Strong evidence

“Guardsmark, LLC provides security services.”

Source: RevenueBase Database · checked Sep 6, 2026
20Indirect evidenceOmaha, NE, United StatesHQ checked Sep 6, 20261,001-5,0001,297 contacts →

Indirect evidence

“More than a provider, we’re an active partner.”

Source: RevenueBase Database · checked Sep 6, 2026
21Strong evidenceWarrendale, PA, United StatesHQ checked Sep 6, 20261,001-5,0001,287 contacts →

Strong evidence

“Vector Security® has protected people and property by providing intelligent security solutions tailored to the needs of the customer for more than 50 years.”

Source: RevenueBase Database · checked Sep 6, 2026
22Strong evidenceDothan, AL, United StatesHQ checked Sep 6, 20261,001-5,0001,190 contacts →

Strong evidence

“DSI Security Services offers armed and unarmed uniformed security guard services.”

Source: RevenueBase Database · checked Sep 6, 2026
23Strong evidenceParsippany, NJ, United StatesHQ checked Sep 6, 202610001+1,151 contacts →

Strong evidence

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

Source: RevenueBase Database · checked Sep 6, 2026
24Strong evidenceChicago, IL, United StatesHQ checked Sep 6, 20261,001-5,0001,138 contacts →

Strong evidence

“At Titan Security Group, we understand that each client is unique, with specific security needs shaped by the type of property and its location.”

Source: RevenueBase Database · checked Sep 6, 2026
25Strong evidenceDavenport, IA, United StatesHQ checked Sep 6, 20261,001-5,0001,120 contacts →

Strong evidence

“Per Mar Security Services is the largest full-service security solutions provider in the Midwest.”

Source: RevenueBase Database · checked Sep 6, 2026

Showing 25 of 6,852 security firms based in the United States

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Security firms based in the United States at a glance

As of Sep 6, 2026
10.8%Verified-email coverage
31.6%Mobile-number coverage
40.1Average contacts per company
11-50Median size (employees)
2.8%Largest-city concentration · New York
Sep 6, 2026Page data refreshed

Companies by employee count

1-10
2,564
11-50
2,373
51-200
1,205
201-500
369
501-1,000
165
1,001-5,000
94
5,001-10,000
26
10001+
30

Freshness & accuracy

How recently the business emails on this list were verified

Email last verified

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 security firms, 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 “security firms”. 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 security firms), 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 security firms, 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, 29,678 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 6, 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.

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 security firms, 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 security firms are there based in the United States?

RevenueBase identified 6,852 security firms 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 security firms?

New York leads with 189 headquartered companies, followed by Los Angeles (170) and Houston (154).

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 29,678 verified decision-maker contacts tracked across these 6,852 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 6, 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.