The dataset comes from The Center for Public Integrity. You can read more about the data and how it was collected in their September 2020 article "National data release sheds light on past polling place changes".
Note: Some states do not have data in this dataset. Several states (Colorado, Hawaii, Oregon, Washington and Utah) vote primarily by mail and have little or no data in this colletion, and others were not available for other reasons.
For states with data for multiple elections, how have polling location counts per county changed over time?
variable class description
election_date date date of the election as YYYY-MM-DD
state character 2-letter abbreviation of the state
county_name character county name, if available
jurisdiction character jurisdiction, if available
jurisdiction_type character type of jurisdiction, if available; one of "county", "borough", "town", "municipality", "city", "parish", or "county_municipality"
precinct_id character unique ID of the precinct, if available
precinct_name character name of the precinct, if available
polling_place_id character unique ID of the polling place, if available
location_type character type of polling location, if available; one of "early_vote", "early_vote_site", "election_day", "polling_location", "polling_place", or "vote_center"
name character name of the polling place, if available
address character address of the polling place, if available
notes character optional notes about the polling place
source character source of the polling place data; one of "ORR", "VIP", "website", or "scraper"
source_date date date that the source was compiled
source_notes character optional notes about the source