A Tale of Two Americas

In any discussion of the makeup of America, it is common to use phrases such as “educated coastal elites” and “conservative middle America”. In response to the proliferation of these geography-based stereotypes, I have created a series of visualizations to better understand what sets coastal and inland America apart.

For the purpose of this exploration, “coastal America” will be defined geographically as the counties in the continental United States that have a coastline on either the Atlantic or Pacific Oceans. “Inland America” will be defined geographically as all the remaining counties, including counties that border the Gulf of Mexico as well as those in Alaska and Hawaii. This creates an objective measure for what is coastal that aligns reasonably well with the areas of the country that self-identify as coastal.

The following is a series of data-visualization driven comparisons of inland and coastal counties on the basis of population, income, immigration, education, and political ideology. Whenever possible the color blue will indicate coastal counties and the color orange will indicate inland counties.

Population - In the visualization above each circle references a county, either coastal or inland, and the size of the circle references the population of that county. The largest county in the United States by a significant margin is Los Angeles County, which has a population of over 10 million. The next three largest counties—Cook County (IL), Harris County (TX), and Maricopa County (AZ)—are all inland. 7 of the 10 largest cities in the US lie in inland counties, although New York City and Los Angeles are both in coastal counties.

A little over three times as many people live in inland counties as in coastal counties, so in terms of total population the two categories are not on equal footing. However, the population density is 8 times higher in coastal counties than inland counties, indicating that people in coastal counties are more likely to live in densely populated areas such as cities. This is reflected moreover by the number of inland counties with relatively small populations. The graphic above shows that there are many more very small counties, population-wise, inland than on the two coasts.

Of course the problem, as with any geography related data visualization, is that no two counties in are the same size. The population of a county is certainly correlated to the land area of that county, so while informative, average county population is not a perfect measure of comparison.

Income - The median household income of people who live in coastal counties ($60,319) is significantly higher than the median household income in inland counties ($48,341). It follows that people who live in coastal counties generally make more money, although the cost of living is generally higher as well.

Moving beyond a comparison of averages, it is also true that income is distributed more equally in inland counties than in coastal counties. The distribution of income in inland counties is what is called normal, meaning on both sides of the median the distribution looks about the same. This means that the majority of counties have median household incomes right around average, and there are few counties with median household incomes that are drastically higher or lower than average.

The same cannot be said for coastal counties. The distribution of incomes in coastal counties is right-skewed, meaning that the most commonly occurring median household incomes are below the median and out to the right there are many counties with household incomes that are significantly higher than average. This indicates that wealth is less evenly shared in coastal counties, where the range of incomes is greater.

Immigration - The chart above shows where the immigrants over the last five years have taken up residence. Clearly, many more people have moved to inland counties than coastal counties in the last five years. This ratio is about 3:1. Notably, the ratio of population in inland counties to coastal counties is also about 3:1. This means that inland counties and coastal counties have grown at about the same rate in the last five years due to the influx of immigrants.

Education - The vertical axis of this plot shows the proportion of the population that has finished various levels of education, while the horizontal axis refers to the number of people in each the coastal and inland counties. Considering these variables together, the area of each box is equivalent to the number of people in America that fall into each bucket.

The narrative that people on the coasts are more educated than people who live inland is generally true. The proportion of people with bachelors degrees is higher (36% to 29%) and proportion of people who have attended at least some college, whether they graduated or not, is higher (64% to 59%). However, the same trend does not hold up on the high school level. Only 12% of the inland population has not obtained a high school degree, compared to 14% in coastal counties. While a greater percentage of people in coastal counties have gone on to higher education, a greater percentage of people in inland counties have achieved a high school diploma.

The most “popular” bucket in coastal counties is to have gotten a bachelors degree or higher. In contrast, the most “popular” level of education in inland counties, if by a small margin, is to have completed some college or achieved a two-year degree. This could be indicative of a high college dropout rate, but it could also be indicative of a greater portion of the population choosing to pursue associates degrees.

Political Ideology - This chart depicts share of the popular vote in coastal counties vs. inland counties in the 2016 presidential election. The results are not surprising, Clinton won the popular vote in coastal counties and Trump won the popular vote in inland counties. Interestingly Clinton won the popular vote in coastal counties by a significantly higher margin than Trump won the popular vote in inland counties. This indicates that the political ideologies of people who live on the two coasts are significantly more polarized than in inland counties. In both inland counties and coastal counties, third-party candidates received 5% of the vote.

Of course, this is a reflection of opinion on Clinton and Trump, and may not be the best reflection of people’s general political ideologies or what the popular vote might look like in the 2020 presidential election.

Data collected from the United States Census Bureau and the Department of Agriculture Economic Research Service. Many graphics are based on 2018 estimates.