When was Johnson County founded?

Johnson County was founded in 1875, formed from Albany County, Carbon County and Sweetwater County, and named after E. P. Johnson.

What is the county seat of Johnson County?

The county seat of Johnson County is Buffalo.

Is there an online parcel map for Johnson County?

Yes. Wyoming Department of Revenue, Property Tax Division (statewide parcels from county assessors) publishes a parcel map of 7,797 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Johnson County's boundary or name changed?

Johnson County was created in 1875 from Albany County, Carbon County and Sweetwater County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Big Horn County, Sheridan County and Albany County. It was formerly called Pease.

Is my lot in a flood zone?

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

County · code 56019

Johnson CountyWyoming

Johnson County is a county in Wyoming with its seat in Buffalo, formed in 1875.

Founded1875
County seatBuffalo
Named forE. P. Johnson
Land area4,154 sq mi + 20 sq mi water
Population8,447 2020 Census
Parcels mapped7,797 checked 15 October 2026

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

Updated 20 October 2026

Census outline · seat marked

History

Formed in 1875 from Albany County, Carbon County and Sweetwater County

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

Originally created as Pease County by Wyoming Territory in 1875 from parts of Albany, Carbon, and Sweetwater Counties, it was renamed Johnson in 1879. The county became fully organized in 1881 and became a county in the state of Wyoming in 1890. Its boundaries shifted in later years as territory was transferred to create neighboring counties and when boundaries were adjusted to federal land survey lines in 1911.

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

1875
Johnson County created Pease (now Johnson) created by Wyoming Territory from Albany, Carbon, and Sweetwater; Pease not fully organized, attached to Albany, Carbon, and Sweetwater "for judicial and all other purposes."
from Albany from Carbon from Sweetwater
8 December 1875 · Whitehead, 199-201
1879
Renamed Pease renamed Johnson.
formerly Pease
13 December 1879 · Wyo. Terr. Laws 1879, 6th leg., ch. 31/p. 47
1888
Lost territory Johnson lost to creation of Sheridan. Sheridan not fully organized, attached to Johnson for administrative and judicial purposes.
to Sheridan
9 March 1888 · Wyo. Terr. Laws 1888, 10th leg., ch. 90, sec. 62/p. 218
1890
Lost territory Johnson lost to creation of Big Horn. Big Horn not fully organized, part attached to Johnson "for judicial, revenue and election purposes."
to Big Horn
12 March 1890 · Wyo. Terr. Laws 1890, 11th leg., ch. 48/pp. 80-83
1890
Became part of Wyoming Johnson became a county in the state of Wyoming. 10 July 1890 · Wyoming Constitution 1889, art. 12 in Swindler, 10:493; U.S. Stat., vol. 26, ch. 664[1890]/pp. 222-226; Van Zandt, 145

Show all 10 changes (5 more)

1875
Johnson County created Pease (now Johnson) created by Wyoming Territory from Albany, Carbon, and Sweetwater; Pease not fully organized, attached to Albany, Carbon, and Sweetwater "for judicial and all other purposes."
from Albany from Carbon from Sweetwater
8 December 1875 · Whitehead, 199-201
1879
Renamed Pease renamed Johnson.
formerly Pease
13 December 1879 · Wyo. Terr. Laws 1879, 6th leg., ch. 31/p. 47
1881
Changed Johnson fully organized, detached from Albany, Carbon, and Sweetwater.
Albany Carbon Sweetwater
10 May 1881 · Trenholm, 1:331
1888
Lost territory Johnson lost to creation of Sheridan. Sheridan not fully organized, attached to Johnson for administrative and judicial purposes.
to Sheridan
9 March 1888 · Wyo. Terr. Laws 1888, 10th leg., ch. 90, sec. 62/p. 218
1888
Changed Sheridan fully organized, detached from Johnson.
Sheridan
11 May 1888 · Trenholm, 1:331
1890
Lost territory Johnson lost to creation of Big Horn. Big Horn not fully organized, part attached to Johnson "for judicial, revenue and election purposes."
to Big Horn
12 March 1890 · Wyo. Terr. Laws 1890, 11th leg., ch. 48/pp. 80-83
1890
Became part of Wyoming Johnson became a county in the state of Wyoming. 10 July 1890 · Wyoming Constitution 1889, art. 12 in Swindler, 10:493; U.S. Stat., vol. 26, ch. 664[1890]/pp. 222-226; Van Zandt, 145
1897
Changed Big Horn fully organized, detached from Johnson.
Big Horn
4 January 1897 · Trenholm, 1:331
1911
Lost territory Johnson lost territory along former boundary with Crook and Weston when boundaries were redefined to run on federal land survey lines. Johnson gained from Natrona when southern boundary was adjusted to run on federal land survey lines. Boundaries with Converse and Sheridan clarified (no change).
to Crook to Weston to Natrona to Converse to Sheridan
21 February 1911 · Wyo. Laws 1911, 11th leg., ch. 77, secs. 5, 7, 9, 11, 14/pp. 106-109, 111, 113
1929
Boundary clarified Boundary between Johnson and Sheridan clarified (no change).
with Sheridanno change
7 February 1929 · Wyo. Laws 1929, 20th leg., ch. 18/pp. 23-24

Land and parcels

What the maps cover in Johnson

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

Parcels Good enough

Lot lines and tax-map numbers for 7,797 parcels from Wyoming Department of Revenue, Property Tax Division (statewide parcels from county assessors). Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 10 June 2026 · checked 15 October 2026
Address points Missing

No public address points layer found for Johnson 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

Johnson by the Census

Population

8,447 2020 Census count

Housing units

4,598 2020 Census count

Land area

4,154 square miles

Water area

20 square miles

People per sq mi

2 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

Johnson 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 Johnson County.
johnsoncountywyoming.org

See your own lot on these maps

Open Johnson 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 Johnson County

When was Johnson County founded?: Johnson County was founded in 1875, formed from Albany County, Carbon County and Sweetwater County, and named after E. P. Johnson.
What is the county seat of Johnson County?: The county seat of Johnson County is Buffalo.
Is there an online parcel map for Johnson County?: Yes. Wyoming Department of Revenue, Property Tax Division (statewide parcels from county assessors) publishes a parcel map of 7,797 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Johnson County's boundary or name changed?: Johnson County was created in 1875 from Albany County, Carbon County and Sweetwater County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Big Horn County, Sheridan County and Albany County. It was formerly called Pease.
Is my lot in a flood zone?: We do not have flood maps for Johnson County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby