The largely unexpected rise in support for Republican and Democratic presidential candidates Donald Trump and Bernie Sanders — who represent two vastly different viewpoints — reflects how polarized Americans are on the political spectrum. The differences can be seen even within states where the political leanings of residents in one county can differ substantially from that of another.
Based on voting data compiled by political news organization Politico and a review of current and historical representation in the U.S. Congress, 24/7 Wall St. created an index to measure the political leanings of county residents nationwide. Prince George’s County is not just the bluest county in Maryland, but also the most Democratic-leaning county in the nation. King County, Texas, on the other hand, is the reddest county in the state and the country.
In a recent report from policy think tank Pew Research Center, researchers found that Republican politicians tend to find their support among financially well-off voters, while the least financially secure Americans are considerably more likely to support Democrats.
While the political opinions and financial circumstances among Americans are far more nuanced, in general, people living in the bluest counties tend to be worse-off financially compared to Republican-leaning areas. Compared to the reddest county, the bluest counties in 32 states have a lower annual median household income.
Democratic-leaning counties tend to have lower incomes, yet adults in these areas also tend to have higher educational attainment rates compared to the reddest counties. In 33 states, the percentage of adults who have attained at least a bachelor’s degree in the bluest county is higher than the comparable percentage in the reddest county of the state.
The racial composition of these areas also seems to be a factor in the political leanings of county residents. While 63% of Americans identify as white, a lower proportion of the population in 28 of the bluest counties identifies as white. On the other hand, the vast majority of residents in most of the reddest counties identify as white. The share of the white population in only three of the reddest counties is lower than it is nationwide.
While numerous measures contribute to a county’s political leaning, including congressional representation, the bluest counties almost always had the highest share of votes for President Barack Obama in 2012 compared to other counties in the state, and those shares were almost always a majority. However, in four of the bluest counties — Douglas, Nebraska; Cherokee, Oklahoma; Tooele, Utah; and Cabell, West Virginia — a majority of adults voted for Republican challenger Mitt Romney.
Some of the bluest counties in several states are not as blue as those in other states. Teton County, Wyoming, for example, has sent a Republican to Congress in each election cycle since 1979, yet gave 54.7% of its vote to Obama in 2012. Similarly, Republican Peter Roskam has served as Representative of Cook County, Illinois, since 2007. Yet, nearly three-quarters of Cook area voters cast their ballots for Obama in 2012.
These are the most Democratic counties in every state.
Editor’s Note: A previous version of this article erroneously stated that all of California’s representatives in the U.S. Congress were Democrats. In fact, all of California’s U.S. Senators are Democrats.