Alger County, Michigan Map with Townships and Land Area

How to use this map

The map opens on the Divisions view with all 9 of Alger County’s municipalities drawn straight from Census boundary files. Click any one to pin it and read its figures: land area in square kilometres, 2020 population and the density that falls out of those two. The tabs above the map change what the shading means. Divisions gives each unit its own colour so you can tell neighbours apart at a glance. Land area shades by size. Satellite drops one metre aerial imagery under the boundaries. Blank outline strips the fill away for printing or tracing.

The figure people misread is land area. Census land area excludes water, so a municipality with a lake or a river frontage looks smaller in the table than it does on the map. Burt is the clearest case here: its boundary encloses 666.54 square kilometres but only 596.95 of that is land, leaving 69.59 as water. If you are measuring something that sits on the ground, use the land figure. If you are measuring something that follows the boundary, use the polygon.

What this county is made of

Alger County holds 8 townships, 1 city. Burt is the largest by land area at 596.95 square kilometres and Munising city the smallest at 13.62, which makes the largest roughly 43.8 times the size of the smallest. The median sits at 208.98 square kilometres, so the spread is wide but most units cluster nearer the middle than the extremes.

Munising township is the largest by population at 2,865, about 32 per cent of the county total. Munising city is the densest at 145.8 people per square kilometre and Grand Island the emptiest at 0.6, a ratio of about 243 to one. Grand Island has 35 people.

Across the whole county the density is 3.7 people per square kilometre. That is the number to hold on to, because it explains the shape of the map: a few dense nodes and a long tail of thinly settled ground, with the average describing almost none of the individual units.

Where the data comes from

Boundaries come from the Census Bureau TIGERweb county subdivision layer, which is the authoritative source for municipal geography in Michigan. Land area is the Census land measurement, which excludes inland water. Population is the 2020 Decennial Census count for each municipality.

The sources are joined on municipality name, and that join is worth checking rather than trusting. The 9 land areas sum to 2,369.95 square kilometres against a published county land area of 2,369.94, which agrees to the hundredth. The 9 with published figures sum to 8,842, which is the published county total to the person.

Aerial imagery, and how it is fitted to the map

The Satellite tab pulls one metre aerial imagery from the USGS National Map. One metre means each pixel covers roughly a square metre of ground, so at full zoom you can pick out individual buildings, field boundaries and the line of a farm track. That resolution matters at this scale. The national and state maps on this site use a NASA composite at five hundred metres per pixel, which is fine for showing where Michigan sits in the country and useless for showing where a municipal line runs.

The boundaries are drawn in an Albers equal area projection fitted to this county, with standard parallels set inside its own latitude range. Equal area matters here because the map is shaded by area: if the projection distorted area, the shading would be lying. The imagery arrives in Web Mercator and is reprojected to match.

A check you can repeat on paper

Take Munising township. Its land area is 523.82 square kilometres and its 2020 population is 2,865. Divide 2,865 by 523.82 and you get 5.47 people per square kilometre, which is what the panel shows rounded to 5.5.

Now check it against the county. Munising township holds 32.4 per cent of the 8,842 people on 22.1 per cent of the 2,369.95 square kilometres. That gap between population share and land share is the whole story of the map in one comparison.

Mistakes that catch people out

Reading polygon area as land area. The map draws boundaries, and boundaries include water. This county encloses 2,644.31 square kilometres of polygon against 2,369.95 of land, so 274.36 is water, about 10.4 per cent.

Assuming a city is bigger than a town. In Michigan those words describe charter type, not size. Munising city is the smallest unit here at 13.62 square kilometres.

Expecting the average to describe a unit. At 3.7 per square kilometre the county average sits between Grand Island at 0.6 and Munising city at 145.8, and matches neither.

Assuming municipal lines follow roads or rivers. Many were surveyed as charter grants or survey townships long before the roads existed. The straight lines on this map are the original survey, not modern infrastructure.

Related Calculators and Reference

• Michigan County Map, for all 83 counties and where Alger sits among them
• United States Map, for the national view and how Michigan compares
• Massachusetts County Map, for the same treatment applied to another New England state
• US Census Bureau Geography, the source for boundaries, land area and population