Sometimes, people ask me how I make my maps
Geographic Information Systems (GIS) software is good for making maps.
I make maps using qgis, a free and open-source gis program. It is a bit clunky and sometimes crashes, but it gets the job done. And recent releases seem much more stable.
For getting started with QGIS, there are many tutorials here.
Most professionals use ArcGIS.
Fortunately there are standard file formats that are readable by most GIS software, such as
So even though entities host their data using ArcGIS, you can still use qgis to make maps.
Download either kml or shapefile, and you can then add a new vector layer
You can also get a lot of data from the US Census. You can create and download tabular data here. Then you will need a shapefile from here. Make sure the year of your shapefile corresponds to they year of your data.