How COVID-19 spreads in Democratic and Republican counties across the US

COVID-19 in Democratic and Republican counties

Table of contents

The coronavirus crisis is unfolding throughout the key stage of the presidential race when the nation is polarized more than ever between Democratic and Republican camps. Can the pandemic propel the shift in the mood of voters and eventually decide who takes control of the Oval Office? 

We merged the voter registration data with the COVID-19 statistics per counties to see if there is a difference in how the disease spreads in Democratic and Republican communities. Our study reveals a substantial gap, both nationwide and within most states. The question remains why this gap exists and what its impact will be on the upcoming elections. Scroll down for 38 infographics.

Key findings

Nationwide comparison of Democratic and Republican counties

The charts below show the dynamics of the spread of COVID-19 in Democratic and Republican counties across the country. During our research, we recognized that New York state (the major hotspot of the disease) created an imbalance, which prompted us to unveil two variations of the data layout: one with and one without New York.

USA, New York included, confirmed cases

Confirmed COVID-19 cases across the USA

USA, New York excluded, confirmed cases

COVID-19 cases across the U.S, New York excluded

USA, % of population infected

Percent of population infected in Democratic and Republican counties across the US

USA, daily increase

Daily COVID-19 infections increase in Democratic and Republican counties

How majority Democratic and majority Republican counties differ on a state level

Shifting the focus to the state level, the charts below demonstrate the difference between the percent of the population infected in Democratic and Republican counties by state. In this section, we looked at the states that have both Republican and Democratic counties. We intentionally excluded the states with homogeneous makeup, where all counties are either Democratic or Republican.


COVID-19 in AL


COVID-19 in AR


COVID-19 in AZ


COVID-19 in CO




COVID-19 in IA









COVID-19 -in MS


New Hampshire

New Jersey

New Mexico

New York

North Carolina



COVID-19 in OK




COVID-19 in TX


COVID-19 in VA


COVID-19 in WA


COVID-19 in WI

West Virginia

COVID-19 in WV

Comparison of solidly Republican and solidly Democratic states

Several American states are either solidly Democratic or solidly Republican, meaning that they have either Democratic or Republican counties only: 

  • Solidly Democratic states include California, Washington, Rhode Island, Connecticut, Maine, Massachusetts, and Vermont. 
  • Solidly Republican states are Idaho, Montana, Wyoming, Utah, North Dakota, South Dakota, Nebraska, Louisiana and Kentucky, Tennessee, South Carolina, and Alaska.

Since there is no split between the Democratic and Republican counties in these states, we chose to compare these Democratic and Republican states to each other. More specifically, we looked at the COVID-19 spread in California vs. all solidly Republican states that, altogether, have a similar population. We also found it interesting to compare Nebraska and Maine, as these two homogeneous states have a similar population number and population density.  

California and Solidly Republican states

COVID-19 in CA vs. Republican states

Maine and Nebraska

COVID-19 in Maine vs. Nebraska


To visualize the dynamics of the spread of COVID-19 in the Democratic and Republican counties, we recognized that we needed to establish the predominant political makeup of the US counties. First, we merged voter registration data with Nuwber’s own demographic and consumer data. This helped us to attribute each county to Democratic or Republican based on the majority principle. For this analysis, a majority is defined by whether more voters registered as either Democratic or Republican in the relevant county. Liberal and Independent voters were excluded from the research.

The results showed that 843 counties were found to be majority Democratic, while 2,299 were majority Republican. 30 states hold both majority Democratic and majority Republican counties. Whereas 21 states were either solidly Democratic or solidly Republican as all counties in these states were discovered to be a majority of either party. After we extracted the information on which states fell under a majority of either party, we overlaid the data on the counties’ prevailing political sentiment with statistics detailing the spread of COVID-19 (taken from Johns Hopkins University). Based on the acquired data, we observed the dynamics of the spread of COVID-19 in Democratic and Republican counties across the US and in each state.

The date range of the coronavirus pandemic spread analyzed in this research: 03/22/2020 – 05/10/2020.

Johns Hopkins University
United States Census Bureau
Nuwber consumer and demographic data

About Nuwber Voter Research

This research is a collaborative effort of Nuwber team conducted to reveal factors and demographic patterns influencing the 2020 presidential race.

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Our report and charts are free and available to all who need them for personal or business use. Please cite this website if you use this publication, publication excerpt, chart or data point in your article, visualization or reporting.