Background: Precincts
Precincts
VTD (voting district) maps from the Decennial Census
State redistricting
Precinct boundary changes by localities
The Virginia Department of Elections reports election results by precinct, so is the smallest unit by which these results can be analyzed.
Virginia Department of Elections
2009 Governor Election Results
The year before each decennial census, precinct boundaries are frozen, with no new changes allowed until after the population data is released two years later. During this time the US Census Bureau produces a map of Voting district (VTD) boundaries, which in Virginia correspond to precinct boundaries. The maps and accompanying shapefiles for the 2010 Census can be used to map election results data for 2009 and 2010. The data from the Virginia Department of Elections in the listed above is combined with the Tiger/Line Shapefile for Suffolk City to create the map below.
2009 Governor Election Results - Suffolk City
2009 Governor Election Results |
US Census Bureau Tiger/Line Shapefiles
This is a tidy system for visualizing election results data, and correlating it with other demographic data available from the census. Unfortunately it is only this way for one year, and after that the VTD maps are pretty much useless for mapping election results.
As soon as census results are available, Virginia changes the boundaries for Congressional, Senate of Virginia, and House of Delegates districts to reapportion them according to the new population data. This last happened in 2011 and will happen again in 2021. The boundaries of the new districts are defined according to the VTD boundary map produced by the Census Bureau.
Virginia Division of Legislative Services Redistricting Map
Redistricting map with 2011 House of Delegates layer
In response to the state redistricting and population data from the census, each locality changes its precinct boundaries to match the new information. Most localities in Virginia produced a new precinct map between 2011-2012, which were used for the first time in the 2011 or 2012. Between each election, localities make changes as needed according to their population by merging, splitting, renaming, and shifting precinct boundaries.
Although many localities individually publish their new precinct maps online, they must be searched for individually, and then converted to the same format to use together. There is no update to the decennial VTD map. It remains in effect to define district boundaries for the entire decade until a new one is produced for the next decennial census. For example, the Virginia House of Delegates has new court-ordered boundaries adopted on 29 Jan 2019 that are in effect for the 2019 November General Election. The precincts used in the wording to describe and map the new districts are the same 2010 VTD boundaries used to define the 2011 House of Delegates districts, even though the precincts are no longer used in practice by most localities for reporting election results.