When was Platte County founded?

Platte County was founded in 1838, and named after Platte River, Nebraska.

What is the county seat of Platte County?

The county seat of Platte County is Platte City.

Is there an online parcel map for Platte County?

Yes. A public source publishes a parcel map of 44,942 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Platte County's boundary or name changed?

Platte County was created in 1838. The Atlas of Historical County Boundaries records no boundary change since.

Is my lot in a flood zone?

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

County · code 29165

Platte CountyMissouri

Platte County is a county in Missouri with its county seat in Platte City. It was formed in 1838 and named after the Platte River.

Founded1838
County seatPlatte City
Named forPlatte River, Nebraska
Land area420 sq mi + 6.5 sq mi water
Population106,718 2020 Census
Parcels mapped44,942 checked 15 October 2026

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

Updated 19 October 2026

Census outline · seat marked

History

Founded in 1838

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

Platte County was created on December 31, 1838, from Non-County Area 28 and Non-County Area 12.

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

1838
Platte County created Platte created from Non-County Area 28 and Non-County Area 12; Non-County Area 28 eliminated. 31 December 1838 · Mo. Laws 1838-1839, pub., pp. 23-25

Land and parcels

What the maps cover in Platte

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

Parcels Good enough

Lot lines and tax-map numbers for 44,942 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 12 September 2024 · checked 15 October 2026
Address points Missing

No public address points layer found for Platte 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

Platte by the Census

Population

106,718 2020 Census count

Housing units

45,307 2020 Census count

Land area

420 square miles

Water area

6.5 square miles

People per sq mi

254 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

Platte County's official site

We have found the county's site but not its offices yet; start there.

County government

County government
The official website of Platte County.
co.platte.mo.us

See your own lot on these maps

Open Platte 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 Platte County

When was Platte County founded?: Platte County was founded in 1838, and named after Platte River, Nebraska.
What is the county seat of Platte County?: The county seat of Platte County is Platte City.
Is there an online parcel map for Platte County?: Yes. A public source publishes a parcel map of 44,942 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Platte County's boundary or name changed?: Platte County was created in 1838. The Atlas of Historical County Boundaries records no boundary change since.
Is my lot in a flood zone?: We do not have flood maps for Platte County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby