When was Genesee County founded?

Genesee County was founded in 1802, formed from Ontario County.

What is the county seat of Genesee County?

The county seat of Genesee County is Batavia.

Is there an online parcel map for Genesee County?

Yes. New York State Geographic Information Systems (GIS) Clearinghouse publishes a parcel map of 28,266 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Genesee County's boundary or name changed?

Genesee County was created in 1802 from Ontario County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Allegany County, Orleans County and Cattaraugus County.

Who issues building permits in Genesee County?

The county's page on building permits: Licenses and Permits. Inside a city or town, ask that city first.

Who issues septic and well permits in Genesee County?

The county's page on septic systems and wells: Health department: septic and well.

Is my lot in a flood zone?

We do not have flood maps for Genesee County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

County · code 36037

Genesee CountyNew York

Genesee County is in New York and has its county seat in Batavia. The county was formed on March 30, 1802, from Ontario County.

Founded1802
County seatBatavia
Land area493 sq mi + 2.4 sq mi water
Population58,388 2020 Census
Parcels mapped28,266 checked 15 October 2026

Open the free map Click any parcel in Genesee County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated 19 October 2026

Census outline · seat marked

History

Formed in 1802 from Ontario County

An old deed may name a county that no longer exists, or a boundary that has since moved.

When created from Ontario County in 1802, Genesee County was not fully organized and remained attached to Ontario for administrative and judicial purposes until March 1803. The county lost territory multiple times: in 1806 to the creation of Allegany County, in 1808 to Cattaraugus, Chautauqua, and Niagara counties, in 1821 to Livingston and Monroe counties, in 1825 to Orleans County, and in 1841 to Wyoming County. In 1826, Genesee County gained territory back from Orleans County.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

1802
Genesee County created Genesee created from Ontario; Genesee not fully organized, attached to Ontario for administrative and judicial purposes.
from Ontario
30 March 1802 · N.Y. Laws 1802, 25th sess., ch. 64/p. 97
1806
Lost territory Genesee lost to creation of Allegany.
to Allegany
7 April 1806 · N.Y. Laws 1806, 29th sess., ch. 162, sec. 1/p. 604
1808
Gained territory Genesee gained from Allegany; lost to creation of Cattaraugus, Chautauqua, and Niagara.
from Allegany from Cattaraugus from Chautauqua from Niagara
11 March 1808 · N.Y. Laws 1808, 31st sess., ch. 40, secs. 1-2/p. 266
1821
Lost territory Genesee lost to creation of Livingston and Monroe.
to Livingston to Monroe
23 February 1821 · N.Y. Laws 1820, 44th sess., ch. 57, sec. 1/p. 46; ch. 58, sec. 1/p. 50
1825
Lost territory Genesee lost to creation of Orleans.
to Orleans
15 April 1825 · N.Y. Laws 1824, 47th sess., ch. 266, sec. 1/p. 326; N.Y. Laws 1825, 48th sess., ch. 181, secs. 1-2/p. 273

Show all 8 changes (3 more)

1802
Genesee County created Genesee created from Ontario; Genesee not fully organized, attached to Ontario for administrative and judicial purposes.
from Ontario
30 March 1802 · N.Y. Laws 1802, 25th sess., ch. 64/p. 97
1803
Changed In March 1803, Genesee was fully organized, detached from Ontario.
Ontario
31 March 1803 · N.Y. Laws 1802, 25th sess., ch. 64/p. 97
1806
Lost territory Genesee lost to creation of Allegany.
to Allegany
7 April 1806 · N.Y. Laws 1806, 29th sess., ch. 162, sec. 1/p. 604
1808
Gained territory Genesee gained from Allegany; lost to creation of Cattaraugus, Chautauqua, and Niagara.
from Allegany from Cattaraugus from Chautauqua from Niagara
11 March 1808 · N.Y. Laws 1808, 31st sess., ch. 40, secs. 1-2/p. 266
1821
Lost territory Genesee lost to creation of Livingston and Monroe.
to Livingston to Monroe
23 February 1821 · N.Y. Laws 1820, 44th sess., ch. 57, sec. 1/p. 46; ch. 58, sec. 1/p. 50
1825
Lost territory Genesee lost to creation of Orleans.
to Orleans
15 April 1825 · N.Y. Laws 1824, 47th sess., ch. 266, sec. 1/p. 326; N.Y. Laws 1825, 48th sess., ch. 181, secs. 1-2/p. 273
1826
Gained territory Genesee gained from Orleans.
from Orleans
1 May 1826 · N.Y. Laws 1826, 49th sess., ch. 269/p. 302
1841
Lost territory Genesee lost to creation of Wyoming.
to Wyoming
19 May 1841 · N.Y. Laws 1841, 64th sess., ch. 196, sec. 1/p. 169

Land and parcels

What the maps cover in Genesee

Who publishes each layer, how good it is, and when we last checked.

Parcels Good enough

Lot lines and tax-map numbers for 28,266 parcels from New York State Geographic Information Systems (GIS) Clearinghouse. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 25 September 2026 · checked 15 October 2026
Address points Official

One point per address, 32,087 in all from NYS Office of Information Technology Services (ITS), Geospatial Services / GIS Program Office (AGOL org 'ShareGIS NY', owner NYSGIS_GPO).
edited 25 September 2026 · checked 14 October 2026
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

Genesee by the Census

Population

58,388 2020 Census count

Housing units

26,013 2020 Census count

Land area

493 square miles

Water area

2.4 square miles

People per sq mi

118 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Who to ask before you build, dig or sell

Official county pages only. We link to them; we do not copy them, because they change.

Inside a city or town, permits usually come from that city rather than the county.

Permits

Health department: septic and wellfrom geneseeny.gov · checked 13 October 2026
Licenses and Permitsfrom geneseeny.gov

GIS and maps

County GIS and maps 585-815-7901from geneseeny.gov · checked 13 October 2026

County government

County government
The official website of Genesee County.
geneseeny.gov

See your own lot on these maps

Open Genesee 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.

Open the free map no sign-in Pro early access

Questions

Common questions about Genesee County

When was Genesee County founded?: Genesee County was founded in 1802, formed from Ontario County.
What is the county seat of Genesee County?: The county seat of Genesee County is Batavia.
Is there an online parcel map for Genesee County?: Yes. New York State Geographic Information Systems (GIS) Clearinghouse publishes a parcel map of 28,266 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Genesee County's boundary or name changed?: Genesee County was created in 1802 from Ontario County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Allegany County, Orleans County and Cattaraugus County.
Who issues building permits in Genesee County?: The county's page on building permits: Licenses and Permits. Inside a city or town, ask that city first.
Who issues septic and well permits in Genesee County?: The county's page on septic systems and wells: Health department: septic and well.
Is my lot in a flood zone?: We do not have flood maps for Genesee County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby