The problem with this idea--and I know I've seen people demonstrate it by showing maps of it--is that this is based on
land, not
people. To take an extreme example, if a county is 100 square miles and has only 5 inhabitants and the majority vote Republican, whereas another county is 10 square miles but has thousands of people and the majority vote Democrat, on a map it'll look like you have a giant Republican area and a tiny Democrat area, even though the population of the latter is dramatically bigger.
And generally speaking, Democrats do well in the places where you have a lot of people packed into a smaller location (that is, the big cities) whereas Republicans do well in the areas where people are more spread out, which means you get large red tracts of land where comparatively fewer people live per square mile, and then some smaller blue areas where a lot of people live.
So, for example, here's a map of Illinois results by county from the 2020 election (taken from
here)
View attachment 356783
We can clearly see that most of the map is red, even though the state was strongly Democrat (Biden won by 17%). The reason for this is that the blue areas have much larger populations than the red ones. Cook County, which contains Chicago and is very blue, is one of the ones in the upper-right area (it's the one with the longer border with the lake). It's not all that big of an area, and doesn't look all that impressive on a map like this. But has a larger population than
every red county in the state combined.
So while one can indeed say a county map showing results is interesting to look at, it also doesn't mean much because it's based on land rather than people. All it's really a demonstration of the fairly well-known fact that Republicans generally do better in rural areas and Democrats generally do better in urban areas.