County Maps US

Bay County, Michigan

A county in Michigan, ranked 20 of 83 by population.

CountyFIPS 26017

Within Michigan
Bay County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data.

Download SVGFull Michigan map downloads

Population
102,123
-1,616 (-1.6%) since 2020
Land area
442.4
square miles. A further 29.9% of the total area is water
Population density
231
people per square mile, computed rather than published
County seat
Bay City
Seat of county government.
Established
1857
168 years ago
Largest city
Bay City city
Population 31,868.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Bay County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Bay County, Michigan from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 553 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Bay County ranks

Position among the 83 counties of Michigan, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MichiganNationally
Population102,12320th of 83613th of 3,144
Land area442.4 sq mi79th of 832,297th of 3,144
Population density231 per sq mi15th of 83523rd of 3,144
Median household income$61,76351st of 831,916th of 3,143

Full data for Bay County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population102,123Vintage 2025 Population Estimates
Population in 2020103,739Vintage 2025 Population Estimates
2020 estimates base?103,863Vintage 2025 Population Estimates
Land area442.4 sq mi2025 Gazetteer Files
Water area188.3 sq mi2025 Gazetteer Files
Total area630.7 sq mi2025 Gazetteer Files
Population density?231 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$61,763American Community Survey 2020-2024 5-Year Estimates
Median home value$152,200American Community Survey 2020-2024 5-Year Estimates
Median age43.9American Community Survey 2020-2024 5-Year Estimates
Households45,103American Community Survey 2020-2024 5-Year Estimates
Housing units48,659American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-465
860 births, 1,325 deaths
Net migration
+152
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Bay County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Arenac CountyMichigan30 mi15,068
Saginaw CountyMichigan30 mi187,688
Tuscola CountyMichigan24 mi52,680
Midland CountyMichigan18 mi83,754
Gladwin CountyMichigan12 mi26,077
Huron CountyMichigan0.6 mi30,530

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 83 counties of Michigan

Open the interactive Michigan county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.