How big is Atlanta’s population? Depending on whom you ask, Atlanta has 510,823 residents.[1] Or maybe it’s 5,157,299.[2] Or even 6,411,149.[3] Those are radically different numbers– has someone been huffing exhaust out by Spaghetti Junction?
No, there are just many different ways to define Atlanta. Let’s take a look at some of those descriptions and how they have evolved over time.
City of Atlanta
One option is to align with Omeretta the Great[4] and restrict your understanding of “Atlanta” to the city limits. But the footprint of the city itself has grown significantly over time, not just its population. Figure 1 below presents an oversimplified look at this growth (treating time in roughly quarter-century chunks):
Figure 1: Growth of the City of Atlanta, 1847-Present
Source: Atlanta Department of City Planning Open Data Portal
As the map (Figure 1) shows above, the City of Atlanta occupied a modest 1-mile radius circle at the time of its initial incorporation in 1847. It expanded gradually over the century that followed, then tripled in land area literally overnight with implementation of the “Plan of Improvement” on New Year’s Day, 1952 . The city grew a bit more in the remainder of the 1950s and 60s. Atlanta’s boundaries were mostly stable from the early 1970s through 2006, when the city annexed the territory comprising NPU Q to the southwest. Most recently, Atlanta annexed the Emory/CDC area in 2018.
Atlanta MSA
A second way of describing Atlanta is in terms of its Metropolitan Statistical Area (MSA)[5], which currently weighs in at 29 counties. Like the city itself, Atlanta’s MSA has grown over time, as presented in Figure 2:
Figure 2: Growth of the Atlanta Metropolitan Statistical Area, 1950-Present
As
Data Source: U.S. Census Bureau, CBSA Delineation Files
As Figure 2 shows, the original MSA definition as set in 1950 included three counties: Cobb, DeKalb, and Fulton; Clayton and Gwinnett were added in 1956 and 1958 respectively. The MSA grew to 15 counties in 1973, to 18 in 1983, to 20 in 1992, to 28 in 2003, and finally to 29 counties in 2013.[6]
Atlanta Regional Commission
If just the city is too small but the 29-county MSA too big, then perhaps the Atlanta Regional Commission‘s (ARC) 11-county region is just right. The ARC was created by an act of the General Assembly in 1971, but it is the also the successor agency to the 2-county Metropolitan Planning Commission formed in 1947 which was then widened to the 5-county Atlanta Region Metropolitan Planning Commission 1960. The ARC grew from those five counties at its inception to the 11-county region we now know. Figure 3 below shows the development of the ARC region over time:
Figure 3: Growth of Atlanta Regional Commission Membership, 1947-Present
Sources: Atlanta Regional Commission: 50 year commemorative report and https://33n.atlantaregional.com/friday-factday/welcome-forsyth-county
But even the ARC is not always consistent in how it defines the Atlanta region. That is because we are constrained by how other jurisdictions and authorities are defined. For example, the ARC provides crucial services as Atlanta’s Area Agency on Aging– but that service area includes only 10 of the 11 ARC member counties. Similarly, the Atlanta Urban Area Security Initiative (UASI), housed at ARC, serves a smaller 5-county area.[7]
In the 33n blog, we use the 11-county region as our default[8], but we may use a different definition if data availability or the policy footprint dictate otherwise.
In Conclusion…
This is all to make an obvious, but easily forgotten point. Because there are many different definitions of the Atlanta region, and because Atlanta as a city and a larger region has evolved over time, we must be attentive not only to whose definition of the region but also what vintage of that definition has been employed when data are presented. For example, population figures will be higher– but population density measures will be lower– if counties outside the urban core are included in any regional definition. Similarly, adding Forsyth County, the wealthiest county in Georgia[9] to the ARC region caused the median income for the region to rise even though nothing actually changed on the ground.
Notes
[1] U.S. Census Bureau, City and Town Population Totals, Vintage 2023
[2] U.S. Census Bureau, Metropolitan and Micropolitan Statistical Areas Population Totals, Vintage 2024, aggregated for the 11-county ARC region.
[3] U.S. Census Bureau, Metropolitan and Micropolitan Statistical Areas Population Totals, Vintage 2024, for the Atlanta MSA.
[4] Sorry, not sorry.
[5] Core-based statistical areas (CBSAs) are delineated according to standards set by the Office of Management and Budget. They consist of groups of counties with a “high degree of economic and social integration” (think commuting patterns) with one or more core urban areas. The most recent iteration of Atlanta’s CBSA, as of July 2023, is officially called the “Atlanta-Sandy Springs-Roswell, GA Metropolitan Statistical Area” and recognizes six principal core cities: Alpharetta, Atlanta, Dunwoody, Marietta, Roswell, and Sandy Springs. CBSAs come in two flavors: metropolitan CBSAs (MSAs) have at least one core city with population over 50,000, while micropolitan CBSAs (μSAs) have at least one core city of population at least 10,000, but none reaching 50,000 population. When two or more adjacent CBSAs have a sufficiently high degree of employment interchange, they can be designated as part of a “Combined Statistical Area” as well. “The Atlanta–Athens-Clarke County–Sandy Springs, GA-AL CSA” spans 42 counties, including (as you probably guessed from the name) one county in Alabama. Atlanta’s CSA includes the Atlanta and Athens-Clarke MSAs, plus the Calhoun, Cedartown, Cornelia, Gainesville, Jefferson, LaGrange, Rome, and Thomaston μSAs. MSAs can also be subdivided into Metropolitan divisions (MDs). The Atlanta MSA is divided into two MDs: Bartow, Cherokee, Cobb, Haralson, and Paulding counties belong to the Marietta, GA Metropolitan Division; the remaining 24 counties make up the Atlanta-Sandy Springs-Roswell, GA Metropolitan Division. For more information about CBSAs, see https://www.census.gov/programs-surveys/metro-micro/about.html.
[6] A couple of asterisks are in order. First, Butts County was added to the MSA in 1973, removed in 1992, and restored in 2003. And Lamar County, located just south of the current MSA boundary, was added to the MSA in 2003 but then removed in 2023 at the same time that Lumpkin County was added, maintaining the number of counties at 29.
[7] For more information about the service areas for ARC programs and more about the ARC mission in general, see https://cdn.atlantaregional.org/wp-content/uploads/arc-brochure-final-2023-2.pdf
[8] But be careful when comparing to older posts, as those predating July 2021 will exclude Forsyth County.
[9] At least as measured by median household income, that is.