When was Calvert County founded?

Calvert County was founded in 1654, formed from Anne Arundel County and Charles County, and named after Baron Baltimore.

What is the county seat of Calvert County?

The county seat of Calvert County is Prince Frederick.

Is there an online parcel map for Calvert County?

Yes. Calvert County publishes a parcel map of 56,785 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Calvert County's boundary or name changed?

Calvert County was created in 1654 from Anne Arundel County and Charles County. Since then the Atlas of Historical County Boundaries records 5 later changes, chiefly involving Anne Arundel County, Charles County and Patuxent County. It was formerly called Calvert and Patuxent.

Who issues building permits in Calvert County?

The county's page on building permits: Permit Fees. Inside a city or town, ask that city first.

Is my lot in a flood zone?

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

County · code 24009

Calvert CountyMaryland

Calvert County is a county in Maryland, with its seat in Prince Frederick. The county was formed on July 3, 1654, from Anne Arundel and Charles counties, and named after Baron Baltimore.

Founded1654
County seatPrince Frederick
Named forBaron Baltimore
Land area213 sq mi + 132 sq mi water
Population92,783 2020 Census
Parcels mapped56,785 checked 15 October 2026

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

Updated 19 October 2026

Census outline · seat marked

History

Formed in 1654 from Anne Arundel County and Charles County

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

Calvert County was created on July 3, 1654, from Anne Arundel and Charles counties. The county was renamed Patuxent on October 20, 1654, then renamed back to Calvert on March 24, 1658. Calvert lost territory to Anne Arundel in 1674, to Charles and St. Marys in 1696 with the creation of Prince Georges, and gained territory from Anne Arundel in 1824.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries.

1654
Calvert County created Calvert created from Anne Arundel and Charles (original, extinct); Charles (original) eliminated. Calvert boundaries are estimated.
from Anne Arundel from Charles
3 July 1654 · Archives of Md., 3:308
1654
Renamed Calvert renamed Patuxent; Patuxent lost to Providence (now Anne Arundel).
formerly Calvert
20 October 1654 · Archives of Md., 1:341, 345, 347
c. 1658
Renamed Patuxent renamed Calvert.
formerly Patuxent
24 March 1658 · Archives of Md., 1:369
1674
Lost territory Calvert lost to Anne Arundel.
to Anne Arundel
6 June 1674 · Archives of Md., 15:39
1696
Lost territory Calvert lost to Charles and St. Marys, and lost to creation of Prince Georges.
to Charlesto St. Marysto Prince Georges
23 April 1696 · Archives of Md., 19:213, 214
1824
Gained territory Calvert gained from Anne Arundel.
from Anne Arundel
24 February 1824 · Md. Laws 1823, ch. 183, sec. 1/pp. 125-126
1825
Boundary clarified Boundary between Calvert and Anne Arundel was clarified (no change).
with Anne Arundelno change
18 February 1825 · Md. Laws 1824, ch. 193/p. 147

Land and parcels

What the maps cover in Calvert

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

Parcels Good enough

Lot lines and tax-map numbers for 56,785 parcels from Calvert County. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 15 October 2026
Address points Missing

No public address points layer found for Calvert County yet.
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

Calvert by the Census

Population

92,783 2020 Census count

Housing units

35,663 2020 Census count

Land area

213 square miles

Water area

132 square miles · 38% of the county, including large bodies of water

People per sq mi

435 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

Permit Feesfrom encompass.calvertcountymd.gov
Permits Schedule & informationfrom calvertcountymd.gov

Zoning and code

Zoning Ordinance Updatefrom calvertcountymd.gov

County government

County government
The official website of Calvert County.
co.cal.md.us

See your own lot on these maps

Open Calvert 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 Calvert County

When was Calvert County founded?: Calvert County was founded in 1654, formed from Anne Arundel County and Charles County, and named after Baron Baltimore.
What is the county seat of Calvert County?: The county seat of Calvert County is Prince Frederick.
Is there an online parcel map for Calvert County?: Yes. Calvert County publishes a parcel map of 56,785 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Calvert County's boundary or name changed?: Calvert County was created in 1654 from Anne Arundel County and Charles County. Since then the Atlas of Historical County Boundaries records 5 later changes, chiefly involving Anne Arundel County, Charles County and Patuxent County. It was formerly called Calvert and Patuxent.
Who issues building permits in Calvert County?: The county's page on building permits: Permit Fees. Inside a city or town, ask that city first.
Is my lot in a flood zone?: We do not have flood maps for Calvert County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby