New Haven County, Connecticut

New Haven County is a county in Connecticut, United States, on the shore of Long Island Sound
about 35 miles southwest of Hartford. It had a population of 864,835 at the 2020 census and
covers 605 square miles (1,567 km2) of land, centred near 41°21′N 72°54′W. Connecticut abolished
county government statewide in 1960, so New Haven County has no county seat and no county
administration today — its postal code is 06510, New Haven’s downtown ZIP, and its
governing work is split between two regional councils of governments described below.

New Haven is the county’s largest city and served as its seat before 1960; it remains the
region’s economic and institutional hub. The county holds 7 chartered cities and 20 towns,
including one consolidated borough-town, and it runs on Eastern Time. Its FIPS code is 09009.

Towns & Villages in New Haven County

All 27 of New Haven County’s municipalities are incorporated towns or cities —
Connecticut has no unincorporated territory and no census-designated places at the town level, so
every entry below is a full municipal government. Seven are chartered as cities (New Haven,
Waterbury, Meriden, Milford, Ansonia, Derby and West Haven); the rest are towns, one of which,
Naugatuck, operates under a consolidated borough-town charter with a mayor and council.

North Haven and New Haven are separate, adjoining towns despite the near-identical name —
North Haven was set off from New Haven in 1786 and has never been part of the city. Hamden, a
town rather than a chartered city, is more populous than four of the county’s seven cities
(Milford, Ansonia, Derby and West Haven). The Naugatuck River, not the town of Naugatuck alone,
gives its name to the whole valley corridor running through Naugatuck, Ansonia, Derby, Beacon
Falls and Waterbury.

ZIP Codes

• 06510 — New Haven (downtown; the city also uses 06511, 06515 and several others by neighborhood)
• 06702 — Waterbury (downtown; the city also uses 06704, 06705, 06706, 06708 and 06710)
• 06514 — Hamden (also 06517 and 06518 for parts of the town)
• 06450 — Meriden
• 06516 — West Haven
• 06460 — Milford
• 06492 — Wallingford
• 06770 — Naugatuck
• 06410 — Cheshire
• 06405 — Branford
• 06512 — East Haven (06513 also serves part of the town)
• 06473 — North Haven
• 06437 — Guilford
• 06488 — Southbury
• 06401 — Ansonia
• 06443 — Madison
• 06483 — Seymour
• 06716 — Wolcott
• 06477 — Orange
• 06471 — North Branford
• 06418 — Derby
• 06478 — Oxford
• 06712 — Prospect
• 06525 — Woodbridge
• 06762 — Middlebury
• 06403 — Beacon Falls
• 06524 — Bethany

Every New Haven County municipality has its own dedicated ZIP code or codes; unlike counties
with unincorporated hamlets, there are no places here served only by a neighbor’s post office.

Geography

The county’s southern edge runs along Long Island Sound from Milford to Guilford, giving nine
towns direct shoreline. Inland, the terrain rises through the Naugatuck Valley — a narrow
industrial corridor cut by the Naugatuck River through Waterbury, Naugatuck, Beacon Falls, Derby
and Ansonia — toward the wooded hills of Bethany, Woodbridge and Prospect. The Quinnipiac
River drains the central towns before reaching New Haven Harbor. Lake Housatonic, formed by the
Stevenson Dam on the Housatonic River, forms part of the county’s western edge in Oxford and
Southbury.

New Haven County borders Fairfield County to the west, Litchfield County to the northwest,
Hartford County to the north and Middlesex County to the east; Long Island Sound forms its entire
southern boundary. A live county profile exists for
Litchfield County and for
Hartford County on this site; Fairfield
County and Middlesex County do not yet have one.

Demographics

New Haven County had a population of 864,835 at the 2020 census, the third-highest of
Connecticut’s eight counties, at a density of about 1,430 people per square mile. New Haven
(134,023) and Waterbury (114,403) are the two largest municipalities and together hold more than
a quarter of the county’s residents. The Census Bureau discontinued standalone county-level
population estimates for Connecticut after June 2022, when it formally recognized the state’s
nine councils of governments as county equivalents; the South Central Connecticut Planning
Region, which covers 15 of this county’s 27 towns, was estimated at 578,741 residents in 2025, up
from 570,487 in 2020.

Economy & Local Life

Healthcare and higher education anchor the county’s economy. Yale University and Yale New
Haven Health, both based in New Haven, form Connecticut’s largest employer group, with tens of
thousands of workers across hospitals, clinics and campus operations. Wallingford is home to a
major Bristol Myers Squibb manufacturing plant and to Amphenol Corporation’s headquarters.
Waterbury and Ansonia still carry their 19th-century identity as brass and copper manufacturing
centers, though the mills themselves have largely closed. Other notable institutions include
Southern Connecticut State University and Albertus Magnus College in New Haven, Quinnipiac
University in Hamden, the University of New Haven in West Haven, and Post University in
Waterbury. The county’s flagship annual event is New Haven’s International Festival of Arts &
Ideas each June, drawing performers and audiences from across the region.

History

The Connecticut General Court constituted New Haven County on May 10, 1666, initially
comprising Milford, New Haven and Guilford; it took its name from the New Haven Colony, founded
in 1638 by Puritan settlers John Davenport and Theophilus Eaton before Connecticut absorbed the
separate colony in 1664. New Haven itself sheltered two of the regicide judges who had signed
Charles I’s death warrant, Edward Whalley and William Goffe, who hid in a cave on West Rock in
1661 to escape royal agents. The county’s best-known 19th-century episode is the Amistad affair:
the 1839 mutiny aboard the schooner Amistad ended with the enslaved Africans aboard held and
tried in New Haven, a case that reached the U.S. Supreme Court in 1841 and ruled in their favor.
Later that century, Waterbury and Ansonia grew into national centers of brass and copper
manufacturing, an industrial base that shaped the Naugatuck Valley towns for generations before
much of it declined after the mid-20th century.

Getting There

Interstate 95 crosses the county’s shoreline towns from Milford to Guilford; Interstate 91 runs
north from New Haven through Hamden, North Haven, Wallingford and Meriden toward Hartford;
Interstate 84 crosses Waterbury; and Route 8 follows the Naugatuck Valley through Derby, Ansonia,
Naugatuck and Waterbury. The Merritt Parkway (Route 15) crosses the southwestern towns from
Milford to Hamden.

• Hartford — 39 miles north via I-91
• New York City — 75 miles southwest via I-95
• Bridgeport — 20 miles southwest via I-95
• Springfield, Massachusetts — 65 miles north via I-91

Tweed New Haven Regional Airport, on the New Haven–East Haven line, offers commercial
service on Avelo Airlines and American Airlines. The nearest major hub is Bradley International
Airport in Windsor Locks, about 40 miles north. New Haven Union Station is the county’s main rail
gateway, served by Amtrak’s Northeast Corridor trains, Metro-North’s New Haven Line to New York
City, Shore Line East to New London, and the Hartford Line to Springfield; Waterbury is the
terminus of Metro-North’s Waterbury Branch, and Meriden and Wallingford have their own Hartford
Line stops.

Frequently Asked Questions

Where is New Haven County?
It is in south central Connecticut, on Long Island Sound, between Fairfield County to the west
and Middlesex County to the east.

What is the population of New Haven County?
864,835 at the 2020 census, Connecticut’s third-most populous county.

How big is New Haven County?
605 square miles (1,567 km2) of land, plus roughly 258 square miles of Long Island Sound water
within its boundary.

Does New Haven County have a county seat?
No. Connecticut abolished county government in 1960; New Haven was the seat before then and
remains the county’s largest city, but there is no county administration today.

How many towns and cities are in New Haven County?
27: seven chartered cities (New Haven, Waterbury, Meriden, Milford, Ansonia, Derby and West
Haven) and 20 towns, including the consolidated borough-town of Naugatuck.

What ZIP codes are in New Haven County?
Every town has at least one of its own; New Haven’s downtown ZIP is 06510 and Waterbury’s is
06702. See the full list above.

Which regional government bodies cover New Haven County?
Two: the South Central Connecticut Planning Region (15 towns, served by SCRCOG) covering the
shoreline and central towns, and the Naugatuck Valley Planning Region (the remaining 12) covering
the western manufacturing corridor.

More counties in this state: Towns and villages in Connecticut.