Company lists · Data refreshed September 2026
Top 25 Site security and monitoring services based in the United States
RevenueBase identified 2,468 site security and monitoring services headquartered in the United States as of September 2026 and tracks 161,842 professional contacts across them, including 19,291 with verified work emails. New York is the largest hub.
This list covers site security and monitoring services 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 29, 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.
The 25 largest site security and monitoring services based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 38,634 contacts → | ||||
Partial evidence “Securitas knows Security.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 4,038 contacts → | ||||
Partial evidence “Excelsior Defense is a security and investigations company based out of St.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 3,592 contacts → | ||||
Indirect evidence “U.S.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 2,174 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 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 2,045 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 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 1,399 contacts → | ||||
Partial evidence “Weiser Security Services is the 11th largest security service provider in the U.S.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 1,375 contacts → | ||||
Partial evidence “Guardsmark, LLC provides security services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 1,190 contacts → | ||||
Partial evidence “DSI Security Services offers armed and unarmed uniformed security guard services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 1,138 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 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 1,120 contacts → | ||||
Partial evidence “Per Mar Security Services is the largest full-service security solutions provider in the Midwest.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 1,062 contacts → | ||||
Indirect evidence “Founded in 1982, St.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 849 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 839 contacts → | ||||
Partial evidence “Securitas knows Security.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 748 contacts → | ||||
Partial evidence “Improving Security.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 702 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 626 contacts → | ||||
Partial evidence “Professional Security Consultants, Inc.(PSC) is a world-class provider of security guard services, patrol, investigations, backgrounds, consulting, security screening & specialty…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 572 contacts → | ||||
Partial evidence “Alert 360 security is a trusted and best-in-class provider of reliable security solutions for homes and businesses.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 569 contacts → | ||||
Strong evidence “Interface Systems combines AI-powered technologies with expert remote video monitoring from its US-based Interactive Security Operations Centers (iSOCs).” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 561 contacts → | ||||
Indirect evidence “ECAM, a GardaWorld company, provides proactive live video surveillance solutions for businesses and properties in cities all across North America.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 519 contacts → | ||||
Partial evidence “Mulligan is a Manhattan-based provider of the finest security and fire safety professionals available.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 490 contacts → | ||||
Partial evidence “Rapid Response Monitoring is a leading provider of professional monitoring services founded in 1992.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 440 contacts → | ||||
Partial evidence “AMAROK™ is a nationwide commercial security company specializing in comprehensive perimeter security using electric fencing and surveillance tools like cameras, lights, and alarms.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 417 contacts → | ||||
Partial evidence “At Kent, we’re able to pull from an unequaled pool of business and security products and services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 395 contacts → | ||||
Partial evidence “Tarian’s vision is to shape a future where safety and security are not only foundations for enduring success but also powerful catalysts.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: site security and monitoring services. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names site security and monitoring services.
- Partial evidence
- Its own public description names part of site security and monitoring services, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name site security and monitoring services. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 2,468 site security and monitoring services based in the United States
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Site security and monitoring services based in the United States at a glance
As of Sep 29, 2026Companies by employee count
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 2,468 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 site security and monitoring services, 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 “site security and monitoring services”. 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 site security and monitoring services), 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 site security and monitoring services, 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, 19,291 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 29, 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.
Site security and monitoring services 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 site security and monitoring services, 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 site security and monitoring services are there based in the United States?
RevenueBase identified 2,468 site security and monitoring services 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 site security and monitoring services?
New York leads with 60 headquartered companies, followed by Houston (47) and Los Angeles (47).
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 19,291 verified decision-maker contacts tracked across these 2,468 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 29, 2026.
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Site security and monitoring services by geography
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- Site security and monitoring services based in Toronto, Canada
- Site security and monitoring services based in Paris, France
- Site security and monitoring services based in Berlin, Germany
- Site security and monitoring services based in Mumbai, India
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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.
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