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Security & Alarm Services in Nassau County, NY

87 security companies listed · Updated Oct 27, 2026

Compare security and alarm companies in Nassau County for cameras, alarms, monitoring and guards, and request quotes.

Avahere lists 87 security companies across 33 Nassau County towns. Of these, 13 show a public phone number, 54 link to a website and 11 list a street address. The most listings are in Garden City (10), Mineola (6), Syosset (6). None of these businesses has claimed its page yet, so the details come from public business records.

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Towns with security & alarm services

33 Nassau County towns, A–Z. Pick yours to see local listings.

Security & Alarm Services in Nassau County: common questions

How many security companies are in Nassau County, NY?
Avahere lists 87 security companies across 33 towns in Nassau County.
Are security companies licensed?
In New York, security guard companies, private investigators and alarm installers are licensed by the Department of State, Division of Licensing Services. Ask for the license number.
How do I get quotes from security companies on Avahere?
Describe your job once and local security companies that fit can reply with questions and quotes. It is free for you and for the businesses, and you decide who to hire, if anyone.
I run a security company business. How do I update my listing?
Find your business and choose "Claim it free". After a quick check you can edit your details, add services and photos, and answer customers at no cost.
Is Avahere free?
Yes. Avahere is free for customers and for businesses. There are no lead fees, and businesses cannot pay to rank higher.

Listings come from public business records and from business owners. Avahere does not show owner names or private contact details. Spot a mistake or want a listing removed? Remove a listing or contact us.