Long Island

Islip, New York

Islip is a Census-designated community in Suffolk County, part of New York's Long Island region, with about 18,500 residents at the 2020 census. Its Census boundary is used for statistics; it is not an incorporated village or a municipal government.

Type: Census place (CDP)
County: Suffolk
Region: Long Island
Population (2020): 18,418

How Islip works

The community name is real. The local government is somewhere else.

Usually, the Town of Islip is the municipal starting point for an address in Islip. A Census-designated place is a statistical community, not a separate city, town, or village government.

The Census boundary does not create a town hall

Islip is mapped so the Census Bureau can publish useful local statistics. The government crosswalk places it in the Town of Islip. Use the exact address because mailing, school, fire, and other service lines can still differ.

Town of Islip page Census explanation of CDPs

Permits and local records follow the governing municipality

Building, zoning, local code, assessment, and tax-payment work follows the city or town that serves the parcel. The post office name or CDP name does not prove which counter owns the form.

Islip building and zoning Islip assessment Government and office map

The school district is a separate map

The current state tax-rate data connects Islip with 12 school districts, including Fire Island, Central Islip, Brentwood, and 9 more. District boundaries can cross municipal lines, so the exact address decides enrollment and the school-tax part of the bill.

NYSED school and district profiles New York school-enrollment guide

Mail, fire, school, county, and municipal lines can differ

A mailing name helps locate the community, but the school district, fire or special district, county, and governing municipality each use their own boundary. The county clerk keeps the recorded deed for the parcel's county.

Suffolk County land records Find the county page

Ordinary example

A resident sees Islip on the mailing address

They do not look for an Islip village office. They match the parcel to the Town of Islip, use that government's building or assessor route, use the county clerk for the deed, and confirm the school district separately.

Property tax snapshot

Parent-government planning range: $5.3–$23.6 per $1,000

The FY2025 state rows for Islip town combine county + parent town/city + school district on a full-value basis. On a $300,000 home, that base is about $1,583–$7,078 a year before STAR, exemptions, and special-district charges.

This Census place has no municipal government of its own. The exact address decides which parent government and school-district rows apply. Treat this as a route to the right records, not a bill estimate for a specific parcel.

Local government

Islip is served by Islip town.

A census-designated place is a named community for Census purposes, not a separate incorporated municipal government. The city or town layer is the practical local-government starting point.

City or town relationship

Islip town

The Census relationship is geographic. It tells you which city or town overlaps this place; the official municipal pages still control the current division of services.

Islip is a Census place, so these offices belong to its governing municipality rather than to a separate Islip government.

Assessment, exemptions, and grievance

Assessment guide

This is the office that owns the assessed-value record and local exemption file.

Town of Islip Assessor

Clerk, licenses, and municipal records

Marriage guide

Use the clerk for the records and licenses this government actually keeps. A village clerk does not automatically own the town's marriage-license work.

Islip Town Clerk

Building, zoning, and land use

Project guide

Start here for local permits, inspections, zoning, and code questions. County health, wetlands, shoreline, or park review can still add another office.

Islip Planning and Development

Property-tax bills and payments

Match the office to the bill in hand. Village, town or city, county, and school taxes do not always use the same collector.

Islip Receiver of Taxes

The listed official office routes were individually reviewed, most recently on July 13, 2026. Confirm current forms, fees, hours, and deadlines with the office before acting.

County records and estate court

Suffolk County Clerk Estate path

Deeds and mortgages usually route through the county clerk outside NYC. Probate and administration route through the county Surrogate's Court.

Municipal relationships: U.S. Census Bureau 2020 New York Block Assignment Files. Census source. Confirm current responsibilities on the official village, city, town, and county pages before acting.

Official starting points