11787 ZIP Code, Smithtown, NY

11787 is a ZIP code in Smithtown, New York in Suffolk County. It covers 15 square miles of land. The closest ZIP codes are 11788, 11754 and 11767. 34,499 people live here in 11,857 households. At about 2,316 people per square mile it has suburban density, and most homes are owner-occupied (87%). Median household income is $143,101, well above the New York median of $85,974; the median age is 46.3, older than most ZIP codes.

Quick facts

Key figures

MeasureValue
Residents34,499
Households11,857
Median household income$143,101
Income per person$62,426
Median age46.3
Homeowners87.3%
Median home value$679,800
Median rent$2,330
Bachelor's degree or higher52.9%
Average commute (minutes)32.4
Households with kids under 1829.0%
Moved in the past year4.6%
Below the poverty line4.8%
Broadband internet95.6%
Speak a non-English language at home12.7%

Household income

% of householdsValue
<$10K4.3%
$10–15K1.7%
$15–25K2.5%
$25–35K1.9%
$35–50K3.2%
$50–75K9.1%
$75–100K10.5%
$100–150K18.8%
$150–200K14.7%
$200K+33.3%

Age

% of all residentsValue
<1010.1%
10–1912.6%
20–247.2%
25–348.4%
35–4410.5%
45–5414.4%
55–6417.5%
65–749.0%
75+10.5%

Tenure

% of housing unitsValue
Owned, with mortgage51.4%
Owned outright34.2%
Rented12.2%
Vacant2.3%

Type of building

% of housing unitsValue
Detached house85.4%
Townhome5.2%
2–4 units1.8%
5–19 units5.1%
20+ units2.0%
Mobile / other0.3%

Businesses in 11787

1,454 business establishments with 18,002 employees (ZIP Codes Business Patterns 2023).

EDDM carrier routes

11787 has 35 USPS carrier routes with 12,152 residential and 1,028 business mailboxes. Open the EDDM route map.

Carrier routes in 11787

11787 has 35 USPS carrier routes (35 city (C)) with 12,152 residential and 1,028 business mailboxes. Routes range from 168 homes (C017) to 561 homes (C033); the median route has 359 homes. The Census counted 11,857 households in 11787 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.

Homes per routeRoutes
1–2496
250–49927
500–7492
750–9990
1,000–1,4990
1,500+0

Best routes in 11787 for…

Most businesses

For B2B offers: office supplies, cleaning, IT, catering and commercial services.

  1. Route C017 — USPS business mailboxes 156, 168 homes
  2. Route C001 — USPS business mailboxes 114, 283 homes
  3. Route C036 — USPS business mailboxes 110, 206 homes
  4. Route C013 — USPS business mailboxes 99, 235 homes
  5. Route C031 — USPS business mailboxes 97, 219 homes

Select these 5 routes on the route map

Every carrier route in 11787

RouteTypeHomesBusinessesEst. median incomeEst. ownersEst. families with kidsEst. moved in past year
C001City283114$177,108———
C003City37515$145,792———
C004City3660$132,994———
C005City29016$141,979———
C006City2780$162,614———
C007City3285$186,552———
C009City23732$141,979———
C010City3702$194,485———
C011City3992$186,917———
C012City38128$175,039———
C013City23599$150,857———
C014City35927$171,955———
C015City3776$176,140———
C016City3481$104,386———
C017City168156$175,039———
C018City32431$132,994———
C019City29216$147,245———
C020City28752$150,857———
C021City42817$132,994———
C023City46518$41,140———
C024City5033$171,955———
C025City4520$41,140———
C026City3901$141,979———
C027City3761$147,245———
C029City3352$200,001+———
C030City40041$150,857———
C031City21997$186,917———
C033City56121$175,039———
C034City32023$150,857———
C035City3673$200,001+———
C036City206110$112,518———
C037City4008$132,340———
C038City47433$132,340———
C039City33620$150,857———
C040City22328$171,955———

Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 11787 on the EDDM route map.

How route demographics are estimated

Mailbox counts come from USPS; demographics are estimates

The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).

How a route gets its figures: the block-group length-share method

We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.

Margins of error

Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.

Different years

USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.

Why some routes show identical figures

Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.

Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.

Nearby ZIP codes

Areas that include 11787

Where it ranks

Mail every home in 11787

Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.

EDDM guides

ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 11787, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.

Frequently asked questions

What city is 11787 in?
11787 is a Smithtown, NY mailing address. By land area, 72% lies inside Smithtown, 12% lies inside Hauppauge, 6% lies inside Village of the Branch and 4% lies inside Nesconset.
What county is 11787 in?
11787 is in Suffolk County.
What is the population of 11787?
About 34,499 people (±1,736), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 35,361.
What is the median household income in 11787?
$143,101 (±$9,183), compared with $85,974 for New York as a whole. Half the households in the ZIP code earn more and half earn less.
How many carrier routes and mailboxes are in 11787?
35 USPS carrier routes with 12,152 residential and 1,028 business mailboxes (13,180 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
What ZIP codes are near 11787?
The closest, measured center to center: 11788 (2.4 mi, Hauppauge), 11754 (3 mi, Kings Park), 11767 (3.4 mi, Nesconset), 11725 (3.7 mi, Commack), 11749 (3.8 mi, Islandia) and 11780 (4.5 mi, St. James).

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.