If your community were a junior prom, a population pyramid would be its photograph.  Girls on the left, boys on the right, all clustered by clique, or in this case, by age group.  These handy planning tools graphically illustrate the age and sex composition of a place (city, state, nation, whatever) in a simple, immediately accessible way and should be included in any analysis of said place whether a proposal submission or comprehensive operational analysis for the board (these are really useful when looking at peer cities).  To illustrate the story telling power of population pyramids, here is a collection of them from real cities and counties that represent archetypes.

Military Redoubt

That long arm of post-adolescent males should be a dead giveaway for a military town, in this case Onslow County, NC, home of Marine Corps Base Camp Lejuene.

Boomerville

In the boomer town, the Gen X’ers just don’t have many children and the younger populations stay flat.  This one is Seattle, but Minneapolis is almost identical

Tourist Mecca

The tourist town has little opportunity for young adults and they clear out as shown here in Narrangasett, RI.

Senior Center

Seniors rule in Sarasota, Fl, but not the ones in high school.  The high concentration of senior citizens puts Sarasota County Transit at among the highest demand response trips per fixed route trip in Florida.

The Norm

The “normal” shape for a city, according to the Census, is a big bulge of baby boomers, narrowing to Gen X and widening again with Gen Y and the millennials.  Marion County, IL, fits almost perfectly save for the large number of 85+ women.  Perhaps they keep livin’ for another year of the Indianapolis 500.

College Town

The overwhelming number of co-eds should instantly reveal the college town, this one the home of the Gators, Gainesville, FL.

Distressed City

Rust  Belt cities in distress like Detroit and Flint, MI, and Youngstown, OH  are characterized by irregularity.  The example here is Camden, NJ, which has been identified as the most dangerous city in the US.

Unusuals

Population pyramids are rarely pyramid-looking but the one at left comes close. It takes lots of steady children to keep the bottom fatter than the middle.  This is Salt Lake City and we can guess the Mormon influence has much to do with its appearance. Note the dip in late teens/early twenties when Mormons go on missions.

Another college town, East Lansing, Michigan, is an interesting case because the population of the city (45,000) is actually smaller than the Michigan State  University enrollment (47,000), which means not even all the students live there.

Dearborn defies description. Having one of the largest Muslim populations in the U.S. it is also in the economically hard hit state of Michigan and really does not fit a pattern.