County administrative profile
Nassau County
New York • FIPS 36059
Nassau County Department of Assessment serves as the identified local county assessor for this jurisdiction. Its public resources are the practical starting point for confirming parcel details, assessed value, tax account information, and the correct route for a valuation question or exemption filing.
Responsible office
Nassau County Department of Assessment
- Authority
- County Assessor
- Phone
- 516-571-1500 (Assessment); 516-571-2090 (Treasurer)
- In-person address
- Nassau County Department of Assessment, 240 Old Country Road, 4th Floor, Mineola, NY 11501
- Public hours
- Monday–Friday, 8:00 a.m.–4:30 p.m. for the Department of Assessment; the Treasurer publishes 9:00 a.m.–4:30 p.m.
Official channels
Go straight to the local source
Use the channel that matches your task. Parcel research, map review, and payment collection may be handled by different offices or platforms within the same county.
Agency website
The primary public homepage identified for this appraisal or assessment authority.
Open official resourceProperty search
Search the active parcel or property account lookup when you need an owner, situs, or assessment record.
Open official resourceGIS parcel map
Open the interactive map when location, parcel boundaries, or neighboring property context matters.
Open official resourceTax collection
Use the identified collection channel for bills, balances, receipts, and payment instructions.
Open official resourceWhat to do next
A practical path from question to official record
Identify the parcel
Start with the property search or GIS map and capture the account, parcel, or situs information shown by the county.
Confirm the timeline
Review the local mailing, payment, exemption, and valuation-review guidance before a statutory window closes.
Keep proof
Save notices, account numbers, submissions, payment confirmations, and correspondence for your transaction file.