Company lists · Data refreshed September 2026

Top 25 Private security contractors based in the United States

RevenueBase identified 4,047 private security contractors headquartered in the United States as of September 2026 and tracks 224,302 professional contacts across them, including 21,098 with verified work emails. New York is the largest hub.

This list covers private security contractors 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 21, 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 21, 2026 86% judged on-target in blind review
4,047Companies
224,302Contacts tracked
21,098Verified emails
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The 25 largest private security contractors based in the United States

Ranked by team size
Top 25 of 4,047 private security contractors based in the United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to private security contractors: 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
1Partial evidenceIrvine, CA, United StatesHQ checked Sep 21, 202610001+62,804 contacts →

Partial 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 21, 2026
2Partial evidenceParsippany, NJ, United StatesHQ checked Sep 21, 202610001+38,634 contacts →

Partial evidence

Securitas knows Security.”

Source: RevenueBase Database · checked Sep 21, 2026
3Partial evidenceSt. Petersburg, FL, United StatesHQ checked Sep 21, 2026n/a4,038 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
4Partial evidencePasadena, CA, United StatesHQ checked Sep 21, 202610001+3,612 contacts →

Partial evidence

“EVERYWHERE SECURITY MATTERS.”

Source: RevenueBase Database · checked Sep 21, 2026
5Indirect evidenceRoswell, GA, United StatesHQ checked Sep 21, 202610001+3,592 contacts →

Indirect evidence

“U.S.”

Source: RevenueBase Database · checked Sep 21, 2026
6Partial evidenceCulver City, CA, United StatesHQ checked Sep 21, 20265,001-10,0002,500 contacts →

Partial 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 21, 2026
7Partial evidenceAurora, IL, United StatesHQ checked Sep 21, 20265,001-10,0002,266 contacts →

Partial 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 21, 2026
8Partial evidenceChattanooga, TN, United StatesHQ checked Sep 21, 20265,001-10,0002,174 contacts →

Partial 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 21, 2026
9Indirect evidenceAnnapolis, MD, United StatesHQ checked Sep 21, 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 21, 2026
10Partial evidenceAnn Arbor, MI, United StatesHQ checked Sep 21, 20261,001-5,0002,022 contacts →

Partial 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 21, 2026
11Partial evidenceHerndon, VA, United StatesHQ checked Sep 21, 202610001+1,949 contacts →

Partial 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 21, 2026
12Indirect evidenceSt. Louis, MO, United StatesHQ checked Sep 21, 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 21, 2026
13Indirect evidenceDenver, CO, United StatesHQ checked Sep 21, 20265,001-10,0001,727 contacts →

Indirect evidence

“HSS is now Tarian!”

Source: RevenueBase Database · checked Sep 21, 2026
14Partial evidenceRaleigh, NC, United StatesHQ checked Sep 21, 20265,001-10,0001,639 contacts →

Partial 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 21, 2026
15Partial evidenceBethesda, MD, United StatesHQ checked Sep 21, 20265,001-10,0001,441 contacts →

Partial 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 21, 2026
16Partial evidenceNew Orleans, LA, United StatesHQ checked Sep 21, 20261,001-5,0001,399 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
17Partial evidenceNew York, NY, United StatesHQ checked Sep 21, 202610001+1,375 contacts →

Partial evidence

“Guardsmark, LLC provides security services.”

Source: RevenueBase Database · checked Sep 21, 2026
18Partial evidenceDothan, AL, United StatesHQ checked Sep 21, 20261,001-5,0001,190 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
19Partial evidenceParsippany, NJ, United StatesHQ checked Sep 21, 202610001+1,151 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
20Partial evidenceChicago, IL, United StatesHQ checked Sep 21, 20261,001-5,0001,138 contacts →

Partial 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 21, 2026
21Partial evidenceDavenport, IA, United StatesHQ checked Sep 21, 20261,001-5,0001,120 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
22Partial evidenceBurbank, CA, United StatesHQ checked Sep 21, 202610001+1,081 contacts →

Partial evidence

“Twenty-five years ago Andrews International (AI) began forming a network of the world’s foremost security authorities and connecting with strategic partners for operations…”

Source: RevenueBase Database · checked Sep 21, 2026
23Indirect evidencePittsburgh, PA, United StatesHQ checked Sep 21, 20265,001-10,0001,062 contacts →

Indirect evidence

“Founded in 1982, St.”

Source: RevenueBase Database · checked Sep 21, 2026
24Partial evidencePearl River, NY, United StatesHQ checked Sep 21, 20265,001-10,0001,050 contacts →

Partial evidence

“Brosnan Risk Consultants, Ltd.(BRC) is a security risk management firm focusing on physical security, emergency security, disaster preparedness and recovery and management…”

Source: RevenueBase Database · checked Sep 21, 2026
25Partial evidenceJoplin, MO, United StatesHQ checked Sep 21, 2026n/a981 contacts →

Partial evidence

“US Security Association Inc is a law enforcement company based out of 2914 E 32nd St, Joplin, Missouri, United States.”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 4,047 private security contractors based in the United States

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Private security contractors based in the United States at a glance

As of Sep 21, 2026
9.4%Verified-email coverage
55.4Average contacts per company
11-50Median size (employees)
3.4%Largest-city concentration · New York
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
1,413
11-50
1,303
51-200
806
201-500
268
501-1,000
124
1,001-5,000
75
5,001-10,000
22
10001+
20

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 4,047 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 private security contractors, 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 “private security contractors”. 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 private security contractors), 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 private security contractors, 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, 21,098 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 21, 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 private security contractors, 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 private security contractors are there based in the United States?

RevenueBase identified 4,047 private security contractors 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 private security contractors?

New York leads with 137 headquartered companies, followed by Los Angeles (112) and Houston (99).

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 21,098 verified decision-maker contacts tracked across these 4,047 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 21, 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.