Company lists · Data refreshed September 2026

Top 25 Defence cybersecurity companies based in Arlington, United States

Name: Defence cybersecurity companies based in Arlington, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 61 companies tracked

RevenueBase identified 61 defence cybersecurity companies headquartered in Arlington, United States as of September 2026 and tracks 1,988 professional contacts across them, including 857 with verified work emails. New York is the largest hub.

This list covers defence cybersecurity companies headquartered in Arlington, 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

61Companies

1,988Contacts tracked

857Verified emails

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The 25 largest defence cybersecurity companies based in Arlington, United States

Ranked by team size

Top 25 of 61 defence cybersecurity companies based in Arlington, United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to defence cybersecurity companies: 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	TWO SIX Technologies	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	501-1,000	647 contacts →
	Indirect evidence “At Two Six Technologies, we build, deploy, and implement innovative products that solve the world’s most complex challenges today.” Source: RevenueBase Database · checked Sep 21, 2026
2	Millennium Corporation	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	201-500	265 contacts →
	Partial evidence “For nearly two decades, Millennium Corporation has been operating on the leading edge of cybersecurity.” Source: RevenueBase Database · checked Sep 21, 2026
3	Cydecor, INC	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	501-1,000	237 contacts →
	Indirect evidence “Cydecor advances national security through innovative end-to-end solutions to our customers around the globe.” Source: RevenueBase Database · checked Sep 21, 2026
4	First Information Technology Services, INC	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	51-200	69 contacts →
	Indirect evidence “Designing Information Security Solutions with YOU in Mind.” Source: RevenueBase Database · checked Sep 21, 2026
5	Sancorp Consulting, LLC	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	51-200	60 contacts →
	Indirect evidence “Sancorp Consulting, LLC is focused on providing tailored, professional solutions in the areas of Insider Threat, Artificial Intelligence/Machine Learning, Identity Activities, and…” Source: RevenueBase Database · checked Sep 21, 2026
6	Tesla Laboratories, INC	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	59 contacts →
	Partial evidence “Tesla Laboratories provides Cyber Security, Intelligence Analysis, Financial Management and Program Management services to the Intelligence Community, the Department of Defense…” Source: RevenueBase Database · checked Sep 21, 2026
7	Cybastion	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	51-200	58 contacts →
	Partial evidence “CYBASTION develops robust world-class cybersecurity solutions tailored to suit the needs of different businesses, governments and public sector entities.” Source: RevenueBase Database · checked Sep 21, 2026
8	System Planning Corporation	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	51-200	47 contacts →
	Indirect evidence “System Planning Corporation (SPC)’s success supporting U.S.” Source: RevenueBase Database · checked Sep 21, 2026
9	ACI Solutions	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	41 contacts →
	Indirect evidence “ACI Solutions is a Secure Cloud and Managed Services Provider with U.S headquarters in Arlington, Virginia.” Source: RevenueBase Database · checked Sep 21, 2026
10	SUN Management	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	33 contacts →
	Partial evidence “Sun Management is a customer focused cybersecurity & advanced network solutions firm providing products and services that help solve your most difficult IT challenges.” Source: RevenueBase Database · checked Sep 21, 2026
11	HLINC	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	27 contacts →
	Indirect evidence “Big Business Capability from a Small Business HLinc delivers holistic solutions to our customers’ needs – we develop, integrate, and implement technological solutions, customized…” Source: RevenueBase Database · checked Sep 21, 2026
12	Groupsense	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	22 contacts →
	Partial evidence “GroupSense is a digital risk protection services company that delivers customer-specific intelligence that dramatically improves enterprise cybersecurity and fraud-management…” Source: RevenueBase Database · checked Sep 21, 2026
13	A2 Labs, LLC	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	21 contacts →
	Partial evidence “Cybersecurity Research and Development firm” Source: RevenueBase Database · checked Sep 21, 2026
14	Strategic Technology Partners	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	19 contacts →
	Partial evidence “STP is an IT services company that specializes in building mission critical infrastructure, applications and cybersecurity systems.” Source: RevenueBase Database · checked Sep 21, 2026
15	Cedelis	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	14 contacts →
	Indirect evidence “CEDELIS is an 8(a) Service-Disabled Minority Veteran-Owned Small Business (SDVOSB) that offers innovative IT services to Federal and Civilian agencies, located in the Washington…” Source: RevenueBase Database · checked Sep 21, 2026
16	Existx	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	13 contacts →
	Indirect evidence “ExistX was founded in 2023 with the goal to combine cutting edge invention with practical implementation in the unique environments our customers demand to solve national security…” Source: RevenueBase Database · checked Sep 21, 2026
17	Hancock & Poole Security INC	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	11 contacts →
	Indirect evidence “Hancock & Poole Security (HPS) Inc.” Source: RevenueBase Database · checked Sep 21, 2026
18	Dowless & Associates, INC	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	11 contacts →
	Indirect evidence “Dowless & Associates was incorporated in Dowless & Associates' competencies include Information and Cyber Security, IT Integration, Organizational Change Management and Integrated…” Source: RevenueBase Database · checked Sep 21, 2026
19	Cynnovative	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	10 contacts →
	Indirect evidence “Cynnovative’s mission: To enable our customers to achieve superiority in the cyber domain by rewriting the laws of cyber and advancing state-of-the-art machine learning and…” Source: RevenueBase Database · checked Sep 21, 2026
20	The Enterprise Security Consultants	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	7 contacts →
	Partial evidence “The Enterprise Security Consultants, LLC (dba TES Consultants) is an 8(a) Woman-Owned Small Business (WOSB) delivering industry leading cybersecurity and information technology…” Source: RevenueBase Database · checked Sep 21, 2026
21	Amches	Indirect evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	7 contacts →
	Indirect evidence “Amches provides Wireless and Cyber Security Solutions using proprietary advanced Agile Methodology to cohesively integrate Program Management, Systems Engineering, and both…” Source: RevenueBase Database · checked Sep 21, 2026
22	Tactibit Technologies	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	6 contacts →
	Partial evidence “Tactibit is a small business serving Federal customers, specializing in Cybersecurity, Cloud Services and IT Operations.” Source: RevenueBase Database · checked Sep 21, 2026
23	Neuvik	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	1-10	6 contacts →
	Partial evidence “Neuvik is a cybersecurity services company organized into cross-discipline offerings focused on integrating assessments and risk management into comprehensive security solutions.” Source: RevenueBase Database · checked Sep 21, 2026
24	Cyberblack	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	1-10	6 contacts →
	Partial evidence “Cyberblack is an Arlington, Virginia based consulting firm that specializes in providing commercial, government and personal solutions in the cybersecurity field.” Source: RevenueBase Database · checked Sep 21, 2026
25	Cystemic Security	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	11-50	4 contacts →
	Partial evidence “Whether it's cybersecurity, cloud computing, data analytics, emerging technologies, or operational guidance, our experts possess the knowledge and skills necessary to deliver…” 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: defence cybersecurity companies. 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 defence cybersecurity companies.
Partial evidence: Its own public description names part of defence cybersecurity companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name defence cybersecurity companies. 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 61 defence cybersecurity companies based in Arlington, United States

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Defence cybersecurity companies based in Arlington, United States at a glance

As of Sep 21, 2026

43.1%Verified-email coverage

32.6Average contacts per company

11-50Median size (employees)

165.6%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

Email recency for this list is measured across the whole United States list rather than for Arlington, so it is reported there. Company counts and contact totals on this page are exact for Arlington, over 61 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 defence cybersecurity companies, 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 Arlington, United States whose own description of what they do matches “defence cybersecurity companies”. 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 defence cybersecurity companies), 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 defence cybersecurity companies, and records with no verified work email. Companies headquartered outside Arlington 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, 857 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.

Defence cybersecurity companies by metro in the United States

Defence cybersecurity companies in New York101
Defence cybersecurity companies in Washington87
Defence cybersecurity companies in Austin71
Defence cybersecurity companies in Arlington61
Defence cybersecurity companies in Houston61
Defence cybersecurity companies in Miami61
Defence cybersecurity companies in Columbia59
Defence cybersecurity companies in Dallas59
Defence cybersecurity companies in San Francisco57
Defence cybersecurity companies in Atlanta52
Defence cybersecurity companies in Chicago47
Defence cybersecurity companies in Reston43
Defence cybersecurity companies in San Diego42
Defence cybersecurity companies in Tampa40
Defence cybersecurity companies in Huntsville38
Defence cybersecurity companies in San Antonio37
Defence cybersecurity companies in Herndon34
Defence cybersecurity companies in Mclean34
Defence cybersecurity companies in Denver33
Defence cybersecurity companies in Los Angeles30
Defence cybersecurity companies in Alexandria28
Defence cybersecurity companies in Ashburn28
Defence cybersecurity companies in Baltimore28
Defence cybersecurity companies in Boston28
Defence cybersecurity companies in Seattle27
Defence cybersecurity companies in Chantilly26
Defence cybersecurity companies in Fairfax26
Defence cybersecurity companies in Sheridan26
Defence cybersecurity companies in Las Vegas25
Defence cybersecurity companies in Orlando25

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 defence cybersecurity companies, 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 defence cybersecurity companies are there based in Arlington, United States?

RevenueBase identified 61 defence cybersecurity companies headquartered in Arlington, 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?

TWO SIX Technologies, headquartered in Arlington, tops this list with the largest team on record.

Which city has the most defence cybersecurity companies?

New York leads with 101 headquartered companies, followed by Washington (87) and Austin (71).

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 857 verified decision-maker contacts tracked across these 61 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.