About a year ago, I decided to dive into learning spatial analysis software, specifically ArcGIS. While I was practicing, I took a look at demographic data for Washington, D.C. In this post, I’m going to share what I found out about how the population is spread across D.C. and where different racial and ethnic groups tend to cluster.
Overall Population Distribution
The population data comes from the U.S. Census (via the open data portal for the District of Columbia). The dataset spans the years 2017-2021 (the ACS Demographic Characteristics for D.C. census tracts).
Washington, D.C.’s total population is 683,154. Within the map shown below, the census-tract maximum is 7,138 people and the minimum is 17 people. Excluding non-residential areas such as the National Mall and areas near the White House, the population appears to be relatively evenly distributed across the city.
Top Four Racial/Ethnic Groups (Black/African American, White, Hispanic/Latino, Asian)
The totals for the four major groups do not exactly match the overall population — likely due to overlapping responses or other survey issues. The four groups shown here are the largest.
- Black/African American: 44.7% (305,109)
- White: 40.5% (276,373)
- Hispanic or Latino: 11.3% (76,982)
- Asian: 4.1% (27,989)
Black/African American vs. White Distribution
After the elimination of discriminatory housing policies in the 1960s, many U.S. cities, including D.C., began to exhibit patterns of residential self-segregation. In the map shown, green represents the white-population share and purple represents the black/African American share. White populations are concentrated in the central and western parts of D.C., whereas black/African American populations are dense in the eastern and southern parts.
Hispanic or Latino
I learned for the first time that the terms “Hispanic” and “Latino” are not the same: broadly, “Hispanic” refers to people from Spanish-speaking countries, and “Latino” refers to people from Latin America or the Caribbean. The map shows Hispanics/Latinos concentrated in the northern parts of Washington, D.C.
Asian
Asians represent a small share (4.1 %) of the total population, but I visualized them nonetheless. The map shows concentration in several downtown-areas near Chinatown and around George Washington University, and some western parts. Note: a strong red hotspot does not imply that this group is large in absolute numbers compared to others—it only shows relative density compared to surrounding areas.
Hot-Spot (Local Moran’s I) Analysis by Race/Ethnicity
Hot-spot analysis is a technique to identify clusters of high or low values in space by computing the Moran’s I statistic (a spatial autocorrelation measure).
In simple terms: on the map, red areas indicate statistically significant clustering of high values (i.e., high concentration), and blue areas indicate clusters of low values (i.e., relative scarcity). White indicates areas that are not statistically significant—perhaps because neighboring regions have mixed values, making interpretations conservative.
Black/African American Hotspots: Eastern and southern D.C. show high clustering of Black/African American populations; the central and western parts show low concentrations relative to the average.
White Hotspots: White populations cluster in central and western D.C., including the Capitol Hill area.
Hispanic or Latino Hotspots: Hispanics/Latinos show clustering in the northern parts of D.C.
Asian Hotspots: Asians are clustered somewhat in the downtown core and north-west areas; again, the absolute numbers are small so one must interpret cautiously.
Summary
Although the overall population of Washington, D.C. is relatively evenly distributed across census tracts, residential patterns by race/ethnicity show stark segmentation. Whites are clustered in the center and west, Black/African Americans in the east and south, Hispanics/Latinos in the north, and Asians in some central and western areas. The hot-spot analysis confirms that these patterns are statistically significant.
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