County · code 24031
Montgomery CountyMaryland
Montgomery County is a county in Maryland with its seat in Rockville, formed in 1776 from Frederick County. The county was named after Richard Montgomery.
- Founded1776
- County seatRockville
- Named forRichard Montgomery
- Land area493 sq mi + 14 sq mi water
- Population1,062,061 2020 Census
- Parcels mapped281,843 checked 15 October 2026
Where it is
Montgomery on the map of Maryland
Maryland has 24 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1776 from Frederick County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Montgomery County was created from Frederick County on October 2, 1776. In 1791, the United States established an unnamed district from land ceded by Maryland and Virginia for the seat of national government, and Montgomery County continued to administer county functions in the ceded area. In 1801, Montgomery County lost territory to the creation of Washington County when the federal government established a circuit court for the seat of national government and created counties to administer judicial and administrative functions, eliminating Montgomery from the District of Columbia. In 1997, Montgomery County gained Takoma Park city from Prince Georges County.
- 1776Montgomery County created Montgomery created from Frederick. · Md., Laws Since 1763, "Proceedings of Convention," 6 Sep. 1776
- 1791Montgomery County created The United States created an unnamed district from land ceded by Maryland and Virginia to be the seat of national government. The district was a square with each corner at a point of the compass and each side ten miles long. Montgomery continued county functions of Maryland in the ceded area. · Richardson, 1:102; Van Zandt, 90
- 1801Lost territory Montgomery lost to creation of Washington (D.C., extinct) when the federal government established a circuit court for the seat of national government (now called the District of Columbia) and created two counties to administer judicial and administrative functions; Montgomery eliminated from the District of Columbia.to Washingtonto D.c.· U.S. Stat., vol. 2, ch. 15 [1801]/pp. 103-108; Bryan, 1:400-401
- 1997Gained territory Montgomery gained Takoma Park city from Prince Georges.from Prince Georges· U.S. Census Bureau, "Significant Changes to Counties and County Equivalent Entities: 1970-Present," http://www.gov/geo/www/tiger/ctychng.html
Land and parcels
What the maps cover in Montgomery
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 281,843 parcels from Montgomery 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 Montgomery 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
Montgomery by the Census
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.
Zoning and code
- Planning and zoning
Department of Permitting Services
- Local Map Amendment Rezoning (PDF)
- Office of Zoning and Administrative Hearings
County government
- County government
The official website of Montgomery County.
See your own lot on these maps
Open Montgomery 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 Montgomery County
- When was Montgomery County founded?
- Montgomery County was founded in 1776, formed from Frederick County, and named after Richard Montgomery.
- What is the county seat of Montgomery County?
- The county seat of Montgomery County is Rockville.
- Is there an online parcel map for Montgomery County?
- Yes. Montgomery County publishes a parcel map of 281,843 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Montgomery County's boundary or name changed?
- Montgomery County was created in 1776 from Frederick County. Since then the Atlas of Historical County Boundaries records 3 later changes, chiefly involving D.c. County, Prince Georges County and Washington County.
- Who issues septic and well permits in Montgomery County?
- The county's page on septic systems and wells: Department of Health and Human Services.
- Is my lot in a flood zone?
- We do not have flood maps for Montgomery County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby