A metropolitan statistical area (MSA) is a grouping of counties, cities, and towns with a high degree of social and economic integration. At the time of this writing, there are 387 such geographies in the United States.
The definitions and boundaries of MSAs are revised periodically to account for shifting patterns in resident population and economic conditions. So, some redrawing of MSA boundaries can shrink their geographies and/or reduce their population counts.
The solid blue line in the FRED graph above shows the annual resident population in the Charleston, West Virginia, MSA between 2000 and 2024. The other two lines represent the counties that made up the MSA during two different periods of time:
- The green dashed line shows the population for Kanawha, Jackson, Boone, Lincoln, and Clay counties, which is what the Charleston MSA included between 2010 and 2020.
- The orange dotted line shows the population for just Kanawha, Boone, and Clay counties, which is what the Charleston MSA included after 2020.
In both cases, when the number of counties in the MSA decreased, the solid blue line showing the MSA population dropped in a stepwise fashion. To learn more about this topic and how different data sources reflect changes in economic boundaries, read this earlier FRED Blog post.
How this graph was created: Search FRED for and select “Resident Population in Charleston, WV (MSA).” From the “Edit Graph” panel, use the “Add Line” tab to search for and select “Resident Population in Kanawha County, WV.” Next, customize the data in Line 2 by searching for “Resident Population in Boone County, WV.” Click on the “Add” button. Repeat the last step to add “Resident Population in Clay County, WV.” Next, type the formula a+b+c and click “Apply.”
Suggested by Diego Mendez-Carbajo.
