For the past eight years, Nassau County’s assessment roll has been frozen. Due to this policy implemented by the prior administration, the County’s assessments were not based on accurate market values.

County Executive Laura Curran has directed the County Assessor to unfreeze the roll and reassess all properties to ensure that the roll is defensible, fair and accurate. There will be updated assessments on all residential and commercial properties on the 2020/2021 tentative assessment roll to be released in January 2019.

For more information please see our frequently asked questions.

Your assessment determines your share of property taxes that the County and your town, school district (other than for the Glen Cove City School District) and any special districts raise to fund their services and operations.
The reassessment has no impact on the amounts included in tax levies.
Towns, school districts and special districts determine their tax levies.
The County’s share of the property tax bill is only 16 cents on the dollar.
Nassau County is only one of two county assessing units in New York State.
Prior to 1938, each town in Nassau County had an assessor and there was no County assessor.
Nassau County is the only county in New York State that must pay property tax refunds for its towns, special districts and most of its school districts.


  1. The County is mailing an assessment disclosure notice to property owners by November 1, 2018. Additionally, to increase transparency, property owners will receive a tax impact notice with information on County Executive Curran's Tax Payer Protection Plan.
  2. After November 1, 2018, you may also find your tentative assessment at –
  3. For the first time, the County is utilizing Prognose, a state-of-the art software program that will provide residents with a comprehensive understanding of their assessments. Residents will be able to access this web-based system from their home computers, smartphones and tablets.
  4. The class one level of assessment will be reduced to .10% from the prior year (when it was .25%) to ensure a defensible, fair and accurate assessment roll.
  5. The County is preparing taxpayer protection legislation for submission to the New York State Legislature to protect residents by transitioning over five-years any relative changes in class one tax burden that couldm otherwise result from the reassessment and the change in the level of assessment.
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