Population Centers Through the Decades

In all of the coverage and analysis surrounding the release of the 2010 Census results, another significant landmark passed by seemingly unnoticed.  Between 2000 and 2010, the center of the metropolitan population moved 3,842 feet to the northwest, to the intersection of 10 Mile and Greenfield in Oak Park.  As of the 2010 Census day of April 1, the center of the Metro Detroit population fell outside of Detroit’s boundaries for the third decade in local history. This movement trend towards the northwest has persisted for decades, driven by continued population loss in Detroit and growth in outlying areas.

How can we determine the “center” of a metropolitan area? Firstly, lets define the metropolitan area; Metro Detroit in this analysis is Wayne, Oakland, and Macomb Counties. There are a number of methods for measuring the population center,  but the most common and widely-used method is a process called “mean center.”  This process identifies the location with the smallest possible sum of squared distances to all residents in the area.  You can imagine the mean center as the center of gravity – the point at which a map weighted only by population would balance perfectly on a pin.

According to our mean center analysis, the center of Metro Detroit’s population crossed 8 Mile in 1985, and shows no sign of turning back.  In 1970, the center of the region’s population was near the intersection of Indiana and McNichols, and has traveled 4.48 miles to the Northwest since.  That’s a rate of more than one and one-half feet a day.

In 1970, this house in the University District marked the center of the region’s population.

Over the past forty years, the center of the metro area has increasingly moved towards outlying suburban areas. Despite rapid growth of many eastern municipalities in Macomb County, the population center has trended west, given significant growth in western Wayne and Oakland Counties.  Today, the center of Metro Detroit population is this Rite Aid parking lot.

By the 2020 Census, however, Oak Park will have to relinquish its crown as the center of Metro Detroit to its neighbor, Southfield.  Municipal leaders in Southfield appear to anticipate this change, having recently changed their city’s motto to “The Center of it All.”  However, Southfield will probably only briefly hold the title, as the center may drift further northwest in years to come.