County · code 09009
New Haven CountyConnecticut
New Haven County is a county in Connecticut, with its seat in the city of New Haven. It was created on May 10, 1666, as one of four original counties established by the Colony of Connecticut.
- Founded1666
- County seatNew Haven
- Named forNew Haven Colony
- Land area604 sq mi + 258 sq mi water
- Population864,835 2020 Census
- Parcels mapped293,174 checked 15 October 2026
Where it is
New Haven on the map of Connecticut
Connecticut has 8 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Founded in 1666
An old deed may name a county that no longer exists, or a boundary that has since moved.
New Haven County was named after New Haven Colony and was established in 1666 as one of Connecticut's original counties. Over its early history, the county gained and lost numerous towns through boundary adjustments with neighboring Hartford and Litchfield Counties, including acquiring Wallingford, Derby, Waterbury, and Wolcott, while ceding Barkhamsted, Colebrook, Hartland, and other towns to Hartford, and losing territory to the creation of Litchfield County in 1751.
- 1666New Haven County created New Haven created by the Colony of Connecticut as one of four original counties. · Conn. Col. Recs., 2:34-35
- 1671Gained territory New Haven gained town of Wallingford from Non-County Area 2. · Conn. Col. Recs., 2:152
- 1675Gained territory New Haven gained town of Derby from Non-County Area 2. · Conn. Col. Recs., 2:248-249
- 1706Gained territory New Haven gained town of New Milford from Non-County Area 2. · Conn. Col. Recs., 5:10
- 1708Gained territory New Haven gained town of Durham from Non-County Area 4; Non-County Area 4 eliminated. · Conn. Col. Recs., 5:51
Show all 18 changes
- 1666New Haven County created New Haven created by the Colony of Connecticut as one of four original counties. · Conn. Col. Recs., 2:34-35
- 1671Gained territory New Haven gained town of Wallingford from Non-County Area 2. · Conn. Col. Recs., 2:152
- 1675Gained territory New Haven gained town of Derby from Non-County Area 2. · Conn. Col. Recs., 2:248-249
- 1706Gained territory New Haven gained town of New Milford from Non-County Area 2. · Conn. Col. Recs., 5:10
- 1708Gained territory New Haven gained town of Durham from Non-County Area 4; Non-County Area 4 eliminated. · Conn. Col. Recs., 5:51
- 1722Gained territory New Haven gained from Non-County Area 2. · Conn. Col. Recs., 6:339
- 1728Gained territory New Haven gained town of Waterbury from Hartford. · Conn. Col. Recs., 7:168
- 1730Lost territory New Haven lost the towns of Barkhamsted, Colebrook, Hartland, Harwinton, New Hartford, Torrington, and Winchester to Hartford. · Conn. Col. Recs., 7:272, 387-390, 445-449
- 1738Lost territory New Haven lost the towns of Canaan, Cornwall, Goshen, Kent, and Norfolk to Hartford. · Conn. Col. Recs., 8:169-171
- 1751
- 1780Lost territory New Haven lost to Litchfield when the town of Watertown was created from town of Waterbury. · Conn. St. Recs., 3:73-75
- 1796Gained territory New Haven gained from Hartford when the town of Wolcott was created from towns of Southington and Waterbury. · Conn. St. Recs., 8:373
- 1796Boundary clarified New Haven boundaries were redefined (no change).no change· Conn. Pub. Acts 1796, pp. 123-124
- 1798Gained territory New Haven gained from Litchfield when the town of Oxford was created from towns of Derby and Southbury, lost to Hartford when town of Berlin gained from town of Wallingford. · Conn. St. Recs., 9:284-285, 311-313
- 1799Lost territory New Haven lost the town of Durham to Middlesex. · Conn. St. Recs., 9:351
- 1807Gained territory New Haven gained the town of Southbury from Litchfield. · Conn. Pub. Acts 1807, p. 771
- 1807Gained territory New Haven gained from Litchfield when the town of Middlebury was created from towns of Southbury, Waterbury, and Woodbury. · Conn. Pub. Acts 1807, p. 800; Conn. Pub. Acts 1808, p. 815
- 1881Boundary clarified New Haven jurisdiction over the waters of Long Island Sound was redefined, in accordance with the redefinition of the state line that took effect 26 February 1881 (no change).no change· Conn. Pub. Acts 1881, ch. 37, sec. 1/p. 19
Land and parcels
What the maps cover in New Haven
Who publishes each layer, how good it is, and when we last checked.
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Parcels Good enough
Lot lines and tax-map numbers for 293,174 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 6 October 2026 · checked 15 October 2026 -
Address points Missing
No public address points layer found for New Haven County yet.
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Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
New Haven by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
See your own lot on these maps
Open New Haven County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about New Haven County
- When was New Haven County founded?
- New Haven County was founded in 1666, and named after New Haven Colony.
- What is the county seat of New Haven County?
- The county seat of New Haven County is New Haven.
- Is there an online parcel map for New Haven County?
- Yes. A public source publishes a parcel map of 293,174 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has New Haven County's boundary or name changed?
- New Haven County was created in 1666. Since then the Atlas of Historical County Boundaries records 15 later changes, chiefly involving Hartford County, Litchfield County and Middlesex County.
- Is my lot in a flood zone?
- We do not have flood maps for New Haven County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby