Company lists · Data refreshed September 2026

Top 25 Security and access control companies based in the United States

RevenueBase identified 5,769 security and access control companies headquartered in the United States as of September 2026 and tracks 182,234 professional contacts across them, including 39,322 with verified work emails and 63,774 with mobile numbers. New York is the largest hub.

This list covers security and access control companies 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, how directly it supports the match, 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 SmartSearch, 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 Match evidence on every row Refreshed Sep 6, 2026 86% judged on-target in blind review
5,769Companies
182,234Contacts tracked
39,322Verified emails
63,774Mobile numbers
Explore all 5,769 companies → Free signup · no credit card · 500 free credits

The 25 largest security and access control companies based in the United States

Ranked by team size
Top 25 of 5,769 security and access control companies based in the United States, ranked by team size, largest first. Data refreshed Sep 6, 2026. Evidence rates how directly each company's own description names security and access control companies: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#CompanyHeadquartersEmployeesContacts
1
Allied UniversalPartial evidence
Irvine, CA, United StatesHQ checked Sep 6, 202610001+62,804

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

Source: company website · checked Sep 6, 2026
2
ConvergintIndirect evidence
Hoffman Estates, IL, United StatesHQ checked Sep 6, 202610001+5,707

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

Source: company website · checked Sep 6, 2026
3
UnemployedPartial evidence
St. Petersburg, FL, United StatesHQ checked Sep 6, 2026n/a4,038

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

Source: company website · checked Sep 6, 2026
4Roswell, GA, United StatesHQ checked Sep 6, 202610001+3,592

“U.S.”

Source: company website · checked Sep 6, 2026
5Alpharetta, GA, United StatesHQ checked Sep 6, 2026n/a2,678

“Since 1987, Automated Systems Design, Inc.(ASD®) a five-time Inc.”

Source: company website · checked Sep 6, 2026
6
EveronPartial evidence
Irving, TX, United StatesHQ checked Sep 6, 20261,001-5,0002,045

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

Source: company website · checked Sep 6, 2026
7Romeoville, IL, United StatesHQ checked Sep 6, 20261,001-5,0001,406

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

Source: company website · checked Sep 6, 2026
8
Vector SecurityPartial evidence
Warrendale, PA, United StatesHQ checked Sep 6, 20261,001-5,0001,287

“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: company website · checked Sep 6, 2026
9North Kansas City, MO, United StatesHQ checked Sep 6, 20261,001-5,0001,276

“Established in Safe Haven Security has grown to become the nation’s largest ADT-authorized dealer, trusted by homeowners and businesses across the country.”

Source: company website · checked Sep 6, 2026
10
DSI Security ServicesPartial evidence
Dothan, AL, United StatesHQ checked Sep 6, 20261,001-5,0001,190

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

Source: company website · checked Sep 6, 2026
11
Titan Security GroupPartial evidence
Chicago, IL, United StatesHQ checked Sep 6, 20261,001-5,0001,138

“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: company website · checked Sep 6, 2026
12
PER MAR Security ServicesPartial evidence
Davenport, IA, United StatesHQ checked Sep 6, 20261,001-5,0001,120

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

Source: company website · checked Sep 6, 2026
13Pittsburgh, PA, United StatesHQ checked Sep 6, 20265,001-10,0001,062

“Founded in 1982, St.”

Source: company website · checked Sep 6, 2026
14
Security 101Partial evidence
West Palm Beach, FL, United StatesHQ checked Sep 6, 2026501-1,000849

Security 101® is a nationwide leader in designing, installing, and maintaining advanced security systems tailored to the unique needs of organizations of all sizes.”

Source: company website · checked Sep 6, 2026
15Uniontown, OH, United StatesHQ checked Sep 6, 202610001+839

Securitas knows Security.”

Source: company website · checked Sep 6, 2026
16
Koorsen Fire And SecurityPartial evidence
Indianapolis, IN, United StatesHQ checked Sep 6, 20261,001-5,000834

“Koorsen Fire & Security is a family-owned operation that has kept homes and businesses safe for more than 70 years.”

Source: company website · checked Sep 6, 2026
17
ADT CommercialIndirect evidence
Boca Raton, FL, United StatesHQ checked Sep 6, 2026n/a799

“ADT Commercial, LLC was acquired by GTCR and is now Everon, LLC.”

Source: company website · checked Sep 6, 2026
18
CPI SecurityPartial evidence
Charlotte, NC, United StatesHQ checked Sep 6, 2026501-1,000763

“For more than 30 years, CPI Security has been a leader in customized home and business security and home automation services.”

Source: company website · checked Sep 6, 2026
19
Northeast Security INCPartial evidence
Westwood, MA, United StatesHQ checked Sep 6, 20261,001-5,000748

“Improving Security.”

Source: company website · checked Sep 6, 2026
20New Haven, CT, United StatesHQ checked Sep 6, 20265,001-10,000736

“Combining the expertise of the industry’s most knowledgeable door opening experts with a comprehensive product offering of leading door and hardware brands, the consultative…”

Source: company website · checked Sep 6, 2026
21
Kastle SystemsIndirect evidence
Falls Church, VA, United StatesHQ checked Sep 6, 2026501-1,000686

“Kastle is a leading provider of property technology solutions, protecting commercial real estate, multi-family residential, global enterprises, educational institutions and…”

Source: company website · checked Sep 6, 2026
22
Guardian ProtectionPartial evidence
Warrendale, PA, United StatesHQ checked Sep 6, 2026501-1,000677

“Protecting homes and businesses since 1950, Guardian Protection is one of the nation's largest and most highly regarded security companies.”

Source: company website · checked Sep 6, 2026
23
Alert 360Partial evidence
Tulsa, TX, United StatesHQ checked Sep 6, 2026501-1,000572

“Alert 360 security is a trusted and best-in-class provider of reliable security solutions for homes and businesses.”

Source: company website · checked Sep 6, 2026
24
Interface SystemsPartial evidence
St Louis, MO, United StatesHQ checked Sep 6, 2026501-1,000569

“Interface Systems combines AI-powered technologies with expert remote video monitoring from its US-based Interactive Security Operations Centers (iSOCs).”

Source: company website · checked Sep 6, 2026
25
Ford Audio-VideoPartial evidence
Oklahoma City, OK, United StatesHQ checked Sep 6, 2026501-1,000564

“Ford AV designs, installs, and services professional and commercial sound, audio-video, network infrastructure, and security surveillance systems for organizations including…”

Source: company website · checked Sep 6, 2026

Showing 25 of 5,769 security and access control companies based in the United States

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Security and access control companies based in the United States at a glance

As of Sep 6, 2026
11-50Median size (employees)
New YorkLargest hub · 112 HQs
63,774Contacts with mobile numbers
Sep 6, 2026Data refreshed

Companies by employee count

1-10
2,487
11-50
2,241
51-200
726
201-500
150
501-1,000
69
1,001-5,000
56
5,001-10,000
6
10001+
14

Verified emails by last verification

0–30
36,276
31–60
2,543
61–90
13
90–180
5
180+
485

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 and access control companies, so some rows will be adjacent to the category rather than pure plays. The description and evidence 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 SmartSearch, 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 and access control companies”. Matching reads each company's description, not its industry code or its name.
What we exclude
Companies whose own description does not clearly place them among security and access control companies, 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 an evidence 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, 39,322 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

How many security and access control companies are there based in the United States?

RevenueBase identified 5,769 security and access control companies 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 and access control companies?

New York leads with 112 headquartered companies, followed by Houston (109) and Miami (74).

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 39,322 verified decision-maker contacts tracked across these 5,769 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.

Ready to reach these companies? Verified emails and direct dials for all 5,769 security and access control companies based in the United States. Start with a free account, no credit card.

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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 SmartSearch, 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.