Company lists · Data refreshed September 2026

Top 25 Cybersecurity contractors based in Herndon, United States

Name: Cybersecurity contractors based in Herndon, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 70 companies tracked

RevenueBase identified 70 cybersecurity contractors headquartered in Herndon, United States as of September 2026 and tracks 17,166 professional contacts across them, including 4,118 with verified work emails. New York is the largest hub.

This list covers cybersecurity contractors headquartered in Herndon, 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

70Companies

17,166Contacts tracked

4,118Verified emails

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The 25 largest cybersecurity contractors based in Herndon, United States

Ranked by team size

Top 25 of 70 cybersecurity contractors based in Herndon, United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to cybersecurity 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Mantech	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	5,001-10,000	9,697 contacts →
	Indirect evidence “MANTECH is more than a technology company.” Source: RevenueBase Database · checked Sep 21, 2026
2	Paragon Systems INC	Partial evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	10001+	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
3	Securitas Critical Infrastructure Services, INC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	10001+	1,118 contacts →
	Indirect evidence “Securitas Critical Infrastructure Services, Inc.(SCIS) is a provider of specialized security and fire services to the highly regulated Nuclear, Aerospace, Defense, Energy, and…” Source: RevenueBase Database · checked Sep 21, 2026
4	Omniplex World Services Corporation	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	1,001-5,000	677 contacts →
	Indirect evidence “OMNIPLEX World Services Corporation is a leader and innovator in delivering professional background investigations, intelligence support, and physical security services to…” Source: RevenueBase Database · checked Sep 21, 2026
5	Zolon Tech INC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	501-1,000	459 contacts →
	Indirect evidence “Zolon Tech, Inc.” Source: RevenueBase Database · checked Sep 21, 2026
6	LTS	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	356 contacts →
	Indirect evidence “From disaster response and automated healthcare kiosks to occupational health services and federal IT consulting, we operate at the intersection of mission-critical need and…” Source: RevenueBase Database · checked Sep 21, 2026
7	Dark Wolf	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	501-1,000	348 contacts →
	Indirect evidence “Dark Wolf provides DevSecOps agile software development, information operations, penetration testing and incident response, applied research and rapid prototyping, machine…” Source: RevenueBase Database · checked Sep 21, 2026
8	Sotera Defense Solutions, INC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	1,001-5,000	214 contacts →
	Indirect evidence “Sotera Defense Solutions (Sotera) has joined KeyW Corporation.” Source: RevenueBase Database · checked Sep 21, 2026
9	Ntrepid LLC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	141 contacts →
	Indirect evidence “The Ntrepid Platform powers the diverse and evolving cyber operations needs of the national security and defense communities and the private sector.” Source: RevenueBase Database · checked Sep 21, 2026
10	Solerity	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	201-500	128 contacts →
	Indirect evidence “Since 1991, Solerity, Inc.” Source: RevenueBase Database · checked Sep 21, 2026
11	Netcentrics	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	122 contacts →
	Indirect evidence “For 30 years, NetCentrics has excelled as an innovative technology solutions provider for the U.S.” Source: RevenueBase Database · checked Sep 21, 2026
12	Foxhole Technology	Partial evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	117 contacts →
	Partial evidence “Foxhole Technology is a thought-leading technology firm offering a robust suite of cybersecurity, software development, systems engineering, and test & evaluation solutions for…” Source: RevenueBase Database · checked Sep 21, 2026
13	Alku Government Solutions	Partial evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	102 contacts →
	Partial evidence “ALKU Government Solutions is a National Security Defense Contractor serving the defense, energy, homeland security and intelligence communities.” Source: RevenueBase Database · checked Sep 21, 2026
14	Indigo IT LLC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	101 contacts →
	Indirect evidence “Founded in 2001, Indigo IT is an award winning information technology consulting and services company.” Source: RevenueBase Database · checked Sep 21, 2026
15	Blackhorse Solutions	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	97 contacts →
	Indirect evidence “BlackHorse Solutions, Inc.” Source: RevenueBase Database · checked Sep 21, 2026
16	Truestone, LLC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	94 contacts →
	Indirect evidence “Truestone provides full lifecycle, business driven technology and information security-oriented services and solutions across the public and private sectors.” Source: RevenueBase Database · checked Sep 21, 2026
17	Stillwater Human Capital LLC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	201-500	85 contacts →
	Indirect evidence “Founded in 2012, Stillwater remains committed to supporting the Veteran community, national security, and the defense sector while evolving into a diversified solutions provider…” Source: RevenueBase Database · checked Sep 21, 2026
18	Integrated Security Technologies, INC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	61 contacts →
	Indirect evidence “Integrated Security Technologies designs, integrates, installs and maintains comprehensive solutions for the most complex and important IT, electronic, physical and cyber security…” Source: RevenueBase Database · checked Sep 21, 2026
19	Chameleon Consulting Group LLC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	59 contacts →
	Indirect evidence “Chameleon Consulting Group, LLC was founded by a small group of professionals with extensive experience in cyber operations, software engineering, data analysis, and physical…” Source: RevenueBase Database · checked Sep 21, 2026
20	AVINT	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	48 contacts →
	Indirect evidence “Your Vision Achieved.” Source: RevenueBase Database · checked Sep 21, 2026
21	Athena Technology Group	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	45 contacts →
	Indirect evidence “Cyber Security (Vulnerability Assessments, 24/7 Operations, Hunt Teams, Risk Management, Cyber Response) Program Management (Acquisition, Financial, Technology Insertion) System…” Source: RevenueBase Database · checked Sep 21, 2026
22	Sphinx Solutions INC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	11-50	38 contacts →
	Indirect evidence “Sphinx Solutions is an entrepreneurial cyber security company that helps private- and public-sector organizations take advantage of solutions that match today’s security…” Source: RevenueBase Database · checked Sep 21, 2026
23	Synapse Business Systems, INC	Indirect evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	35 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 21, 2026
24	Network Depot	Partial evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	34 contacts →
	Partial evidence “Network Depot has been serving the DC Metro area since 1991, providing technical support and cybersecurity consulting.” Source: RevenueBase Database · checked Sep 21, 2026
25	Rssi Onezero Solutions	Partial evidence	Herndon, VA, United StatesHQ checked Sep 21, 2026	51-200	33 contacts →
	Partial evidence “In October 2021, OneZero Solutions, LCC (OneZero), a leading federal cybersecurity and IT solutions provider, announced its acquisition of Right-Sized Solutions Inc.(RSSi), a…” Source: RevenueBase Database · checked Sep 21, 2026

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: cybersecurity contractors. 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 cybersecurity contractors.
Partial evidence: Its own public description names part of cybersecurity contractors, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name cybersecurity contractors. 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 70 cybersecurity contractors based in Herndon, United States

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Cybersecurity contractors based in Herndon, United States at a glance

As of Sep 21, 2026

24.0%Verified-email coverage

245.2Average contacts per company

51-200Median size (employees)

418.6%Largest-city concentration · New York

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured across the whole United States list rather than for Herndon, so it is reported there. Company counts and contact totals on this page are exact for Herndon, over 70 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 cybersecurity 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 Herndon, United States whose own description of what they do matches “cybersecurity 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 cybersecurity 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 cybersecurity contractors, and records with no verified work email. Companies headquartered outside Herndon 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, 4,118 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.

Cybersecurity contractors by metro in the United States

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 cybersecurity 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 cybersecurity contractors are there based in Herndon, United States?

RevenueBase identified 70 cybersecurity contractors headquartered in Herndon, 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?

Mantech, headquartered in Herndon, tops this list with the largest team on record.

Which city has the most cybersecurity contractors?

New York leads with 293 headquartered companies, followed by Washington (220) and Austin (170).

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 4,118 verified decision-maker contacts tracked across these 70 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.