Parcel Chartplaces Open the free map

County · code 26147

St. Clair CountyMichigan

St. Clair County is in Michigan, with its county seat at Port Huron. The county was created in 1821 from Macomb County and named after the St. Clair River and Lake Saint Clair.

  • Founded1821
  • County seatPort Huron
  • Named forSt. Clair River and Lake Saint Clair
  • Land area722 sq mi + 115 sq mi water
  • Population160,383 2020 Census
  • Parcels mapped77,122 checked 16 October 2026
Open the free map Click any parcel in St. Clair County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated

MacombSanilacLapeer Port Huron Census outline · seat marked

Where it is

St. Clair on the map of Michigan

Michigan has 83 counties and county equivalents, each with its own records office. Shapes with a page are links.

Alcona CountyAlger CountyAllegan CountyAlpena CountyAntrim CountyArenac CountyBaraga CountyBarry CountyBay CountyBenzie CountyBerrien CountyBranch CountyCalhoun CountyCass CountyCharlevoix CountyCheboygan CountyChippewa CountyClare CountyClinton CountyCrawford CountyDelta CountyDickinson CountyEaton CountyEmmet CountyGenesee CountyGladwin CountyGogebic CountyGrand Traverse CountyGratiot CountyHillsdale CountyHoughton CountyHuron CountyIngham CountyIonia CountyIosco CountyIron CountyIsabella CountyJackson CountyKalamazoo CountyKalkaska CountyKent CountyKeweenaw CountyLake CountyLapeer CountyLeelanau CountyLenawee CountyLivingston CountyLuce CountyMackinac CountyMacomb CountyManistee CountyMarquette CountyMason CountyMecosta CountyMenominee CountyMidland CountyMissaukee CountyMonroe CountyMontcalm CountyMontmorency CountyMuskegon CountyNewaygo CountyOakland CountyOceana CountyOgemaw CountyOntonagon CountyOsceola CountyOscoda CountyOtsego CountyOttawa CountyPresque Isle CountyRoscommon CountySaginaw CountySt. Joseph CountySanilac CountySchoolcraft CountyShiawassee CountyTuscola CountyVan Buren CountyWashtenaw CountyWayne CountyWexford CountySt. Clair County St. Clair
Counties of Michigan · St. Clair highlighted

History

Formed in 1821 from Macomb County

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

ST. Clair was created by Michigan Territory from Macomb in 1821. Over the following decades, ST. Clair lost territory to new counties and surrounding areas were attached for judicial purposes, including parts of Sanilac and Huron. By 1850, ST. Clair had largely reached its current boundaries after Huron was detached and attached to Sanilac for judicial and representative purposes.

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

  1. 1821
    St. Clair County created St. Clair created by Michigan Territory from Macomb.
    from Macomb
    · Terr. Papers U.S., 11:39-40, 133
  2. 1822
    Lost territory St. Clair lost to Macomb and lost to creation of Lapeer, Saginaw, Sanilac, and Shiawassee.
    to Macombto Lapeerto Saginawto Sanilacto Shiawassee
    · Terr. Papers U.S., 11:308-313
  3. 1833
    Lost territory St. Clair lost to Macomb.
    to Macomb
    · Mich. Terr. Laws, 3:926
  4. 1840
    Lost territory St. Clair lost part of Sanilac attachment to creation of Huron; Sanilac detached from Lapeer, re-attached to St. Clair "for judicial purposes."
    to Sanilacto Huronto Lapeer
    · Mich. Acts 1840, ann. sess., no. 119, secs. 1, 4, 33-35/pp. 196, 200
  5. 1848
    Lost territory St. Clair lost to Sanilac.
    to Sanilac
    · Mich. Acts 1848, ann. sess., no. 228/p. 344
Show all 10 changes (5 more)
  1. 1821
    St. Clair County created St. Clair created by Michigan Territory from Macomb.
    from Macomb
    · Terr. Papers U.S., 11:39-40, 133
  2. 1822
    Lost territory St. Clair lost to Macomb and lost to creation of Lapeer, Saginaw, Sanilac, and Shiawassee.
    to Macombto Lapeerto Saginawto Sanilacto Shiawassee
    · Terr. Papers U.S., 11:308-313
  3. 1827
    Changed Sanilac detached from Oakland, attached to St. Clair "for judicial purposes."
    SanilacOakland
    · Mich. Terr. Laws, 2:588
  4. 1833
    Lost territory St. Clair lost to Macomb.
    to Macomb
    · Mich. Terr. Laws, 3:926
  5. 1836
    Changed Part of Sanilac was detached from St. Clair, attached to Lapeer "for judicial purposes."
    SanilacLapeer
    · Mich. Acts 1836, ann. sess., p. 67
  6. 1840
    Lost territory St. Clair lost part of Sanilac attachment to creation of Huron; Sanilac detached from Lapeer, re-attached to St. Clair "for judicial purposes."
    to Sanilacto Huronto Lapeer
    · Mich. Acts 1840, ann. sess., no. 119, secs. 1, 4, 33-35/pp. 196, 200
  7. 1844
    Changed Huron detached from Saginaw, attached to St. Clair "for judicial purposes."
    HuronSaginaw
    · Mich. Acts 1844, ann. sess., no. 78/p. 112
  8. 1848
    Lost territory St. Clair lost to Sanilac.
    to Sanilac
    · Mich. Acts 1848, ann. sess., no. 228/p. 344
  9. 1849
    Changed Sanilac fully organized, detached from St. Clair.
    Sanilac
    · Mich. Acts 1848, ann. sess., no. 228/p. 344
  10. 1850
    Changed Huron detached from St. Clair, attached to Sanilac "for judicial and representative purposes."
    HuronSanilac
    · Mich. Acts 1850, ann. sess., no. 212/p. 215

Land and parcels

What the maps cover in St. Clair

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

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

St. Clair by the Census

Population
160,383 2020 Census count
Housing units
72,092 2020 Census count
Land area
722 square miles
Water area
115 square miles
People per sq mi
222 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

St. Clair County's official site

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

County government

See your own lot on these maps

Open St. Clair 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 St. Clair County

When was St. Clair County founded?
St. Clair County was founded in 1821, formed from Macomb County, and named after St. Clair River and Lake Saint Clair.
What is the county seat of St. Clair County?
The county seat of St. Clair County is Port Huron.
Is there an online parcel map for St. Clair County?
Yes. A public source publishes a parcel map of 77,122 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has St. Clair County's boundary or name changed?
St. Clair County was created in 1821 from Macomb County. Since then the Atlas of Historical County Boundaries records 9 later changes, chiefly involving Sanilac County, Huron County and Lapeer County.
Is my lot in a flood zone?
We do not have flood maps for St. Clair County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby

Counties next door