From Maine to California, thousands of communities across the United States historically practiced - and in some cases, still practice - a form of racial segregation by excluding racial or ethnic groups through some combination of discriminatory local laws, intimidation, or violence. These communities are sometimes called “sundown towns” because members of discriminated groups were expected to be out of town by sundown (meaning they could not live there).

When I was first learning about sundown towns, I came across the work of Dr. James Loewen, a pre-eminent sociologist and social justice activist. In 1999, Dr. Loewen began a public database of sundown towns identified through research by himself and other contributors, a project he continued to grow until his death in the summer of 2021. He also published his findings in his book Sundown Towns: A Hidden Dimension of American Racism.

An opportunity to collaborate

As someone who regularly builds web maps, I recognized an opportunity to make the sundown towns database easier to navigate using an interactive map. The original map on the website let users navigate to a list of towns by state, but did not visually communicate the full extent of the data across the entire country.

I reached out to Dr. Loewen and volunteered to build a new map for the project, as a Mapbox Community project. Dr. Loewen was excited to accept as it turns out it had been a longtime goal to add a more full-featured map to the site. With help from his team of volunteers who were building a new version of the database and website, I got to work.

From list to geojson

The foundation of any map project is data. The sundown towns team figured out a way to serve the database records through an API that I could add as a data layer on the new map. I added layer filtering functionality to help users tailor what data to view. Thanks to a streamlined, live API endpoint and Mapbox GL JS’ addSource functionality, the interaction is snappy and the map is quick to load, even when displaying all the location points at once.‍

“We had long been aware of the limits of exploring the sundown town research via lists of towns in each state. We had been discussing ways to create a new map that would allow additional ways to interpret the research. Sam's vision was a great match with what we wanted in a map.”
- Stephen Berrey, Associate Professor of American Culture and History, University of Michigan

Co-design decisions

For the visual design of the map, I was inspired to use a style that conveyed the somberness of the data subject as well as the academic research of the larger project. I chose a relatively muted base color palette inspired by historical books and then highlighted the data with bold colors, starting with various grays and eventually settling on shades of red to black, which stood out clearly on the map style and website. We used a red flag icon to mark towns “of special interest” identified by the researchers.

Because there are so many locations, at first I tried clustering the data points. However, the research team preferred the visual impact of having all the points visible, like a dot density map.

I worked closely with Dr. Loewen and his team, taking feedback from them and making styling adjustments along the way. Thanks to the ease of making styling changes in Mapbox Studio, we could test different icons and color variations quickly. Being able to translate feedback into visual prototypes for my collaborators to see the impact of styling choices made the process much smoother.‍

“The new map has been a valuable addition to our website. As it visually illustrates the pervasiveness of sundown towns across the country, it also allows users to zoom into a smaller area and quickly get a snapshot of this practice in that region. It allows for geographic understandings of sundown towns that could not be conveyed in the previous format.”
- Stephen Berrey, Associate Professor of American Culture and History, University of Michigan‍

Maps for racial justice‍

The history and ongoing impacts of sundown towns may be a misunderstood and overlooked part of the US social landscape. The data collected by Dr. Loewen and his team uncovers that history and invites everyone to think critically about reasons behind why people live and don’t live where they do today. The new interactive map helps people to understand the extent of this history, and engage with it.

If you know of an organization working for racial or social justice, and you have map or web skills - offer to help out! And connect them with the Mapbox Community team for further support.