Company lists · Data refreshed September 2026

Top 25 Security monitoring service providers based in the United States

RevenueBase identified 3,404 security monitoring service providers headquartered in the United States as of September 2026 and tracks 198,829 professional contacts across them, including 26,851 with verified work emails and 62,433 with mobile numbers. New York is the largest hub.

This list covers security monitoring service providers 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
3,404Companies
198,829Contacts tracked
26,851Verified emails
62,433Mobile numbers
Explore all 3,404 companies → Free signup · no credit card · 500 free credits

The 25 largest security monitoring service providers based in the United States

Ranked by team size
Top 25 of 3,404 security monitoring service providers 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 monitoring service providers: 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
2Parsippany, NJ, United StatesHQ checked Sep 6, 202610001+38,634

Securitas knows Security.”

Source: company website · checked Sep 6, 2026
3
Inter-Con SecurityPartial evidence
Pasadena, CA, United StatesHQ checked Sep 6, 202610001+3,612

“EVERYWHERE SECURITY MATTERS.”

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
5
Arctic WolfIndirect evidence
Eden Prairie, MN, United StatesHQ checked Sep 6, 20261,001-5,0003,145

“Every year new technologies, vendors, and solutions emerge-yet despite this constant innovation, high-profile breaches are all over the headlines.”

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
7
Paragon Systems INCPartial evidence
Herndon, VA, United StatesHQ checked Sep 6, 202610001+1,949

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

Source: company website · checked Sep 6, 2026
8Romeoville, 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
9New Orleans, LA, United StatesHQ checked Sep 6, 20261,001-5,0001,399

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

Source: company website · checked Sep 6, 2026
10
GuardsmarkPartial evidence
New York, NY, United StatesHQ checked Sep 6, 202610001+1,375

“Guardsmark, LLC provides security services.”

Source: company website · checked Sep 6, 2026
11
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
12North 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
13
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
14
SOS Security LLCPartial evidence
Parsippany, NJ, United StatesHQ checked Sep 6, 202610001+1,151

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

Source: company website · checked Sep 6, 2026
15
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
16
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
17Pittsburgh, PA, United StatesHQ checked Sep 6, 20265,001-10,0001,062

“Founded in 1982, St.”

Source: company website · checked Sep 6, 2026
18
Brosnan Risk ConsultantsPartial evidence
Pearl River, NY, United StatesHQ checked Sep 6, 20265,001-10,0001,050

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

Source: company website · checked Sep 6, 2026
19
First Coast SecurityIndirect evidence
Jacksonville, FL, United StatesHQ checked Sep 6, 20265,001-10,000932

“As an established mid-market company, clients throughout the country entrust us as the best-qualified firm to protect their highest-value assets – while delivering the quality…”

Source: company website · checked Sep 6, 2026
20
DefendersPartial evidence
Indianapolis, IN, United StatesHQ checked Sep 6, 20261,001-5,000885

“DEFENDERS is a leader in the home security industry, providing safety and peace of mind to more than 1.5 million families nationwide.”

Source: company website · checked Sep 6, 2026
21
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
22Uniontown, OH, United StatesHQ checked Sep 6, 202610001+839

Securitas knows Security.”

Source: company website · checked Sep 6, 2026
23
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
24
Northeast Security INCPartial evidence
Westwood, MA, United StatesHQ checked Sep 6, 20261,001-5,000748

“Improving Security.”

Source: company website · checked Sep 6, 2026
25San Antonio, TX, United StatesHQ checked Sep 6, 2026201-500702

“Pro-Vigil is the smartest, fastest, most reliable, surveillance and monitoring solution, to enable you to focus on your core business, whether that’s in construction, an auto…”

Source: company website · checked Sep 6, 2026

Showing 25 of 3,404 security monitoring service providers based in the United States

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Security monitoring service providers based in the United States at a glance

As of Sep 6, 2026
11-50Median size (employees)
New YorkLargest hub · 71 HQs
62,433Contacts with mobile numbers
Sep 6, 2026Data refreshed

Companies by employee count

1-10
1,279
11-50
1,273
51-200
533
201-500
148
501-1,000
68
1,001-5,000
61
5,001-10,000
10
10001+
19

Verified emails by last verification

0–30
24,750
31–60
1,617
61–90
11
90–180
2
180+
471

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 monitoring service providers, 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 monitoring service providers”. 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 monitoring service providers, 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, 26,851 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 monitoring service providers are there based in the United States?

RevenueBase identified 3,404 security monitoring service providers 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 monitoring service providers?

New York leads with 71 headquartered companies, followed by Houston (65) and Los Angeles (55).

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 26,851 verified decision-maker contacts tracked across these 3,404 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 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.