A guest blog by Adam Pagnucco.

The data below combines precinct information with census tract data on Hispanic origin and race from the 2010 Decennial Census.  The demographics of the three counties are very different.  Of the 67 precincts in Carroll and Frederick Counties, 63 had populations that were at least 90% white.  Of the 139 precincts in Montgomery County, 57 were majority-minority.  These differences influence the presentation below.

Here are the results for precincts by their population percentages in different demographic categories.

At first glance, the data shows a seeming contradiction.  Trone led in precincts with populations over 75% white.  But Trone also led in precincts with less than 40% white populations.  How can this be?  The former fact is explained by Trone’s victory in the overwhelmingly white precincts of Carroll and Frederick.  The latter fact is explained by Trone’s wins in Gaithersburg, Glenmont/Norbeck and parts of Rockville, which are racially diverse.  Trone also finished a close second in Wheaton and Silver Spring East County.  While Senator Jamie Raskin won big in diverse precincts in Takoma Park and Silver Spring Inside the Beltway, he also won in predominantly white Bethesda, Cabin John, Chevy Chase and Kensington.  Delegate Ana Sol Gutierrez was a factor in Glenmont/Norbeck (Zip Code 20906 excluding Leisure World), finishing second in the nine precincts there.  She finished third in the 19 precincts with at least 33% Hispanic populations.

We will have a summary of the candidates’ performance in Part Four.