Los Angeles County mail-ballot processing center in Pomona, California. The facility was the largest vote-by-mail processing center in the country during the 2020 election. 
Mail ballots delivery. 
Ballots cast by mail in Los Angeles County. 
Preparing ballots for processing. 
Ballots being loaded into automated signature verification machine. 
Automated signature verification. 
Manual signature verification. 
Manual signature verification. 
Ballots being re-packed for further processing. 
Ballot envelope opener. 
Automated ballot envelope opener machine. 
Ballots are extracted from their envelopes. 
Ballots are extracted by hand and manually verified for completeness. 
Ballots are extracted by hand and manually verified for completeness. 
Ballots are extracted by hand and manually verified for completeness. 
Ballots are extracted by hand and manually verified for completeness. 
Ballots that are not complete are send to a team for manual curing with voters. 
Ballots re repacked for transport. 
Tamper-proof tape applied to ballot transport boxes. 
Ballot from distant parts of the county are flown to the tally center by helicopter. 
LA Country Sheriffs maintain chain of custody during ballot transport. 
Inside the vote tally operation center in Los Angeles County on election night 11/3/20 
LA Country Sheriffs maintain chain of custody during ballot transport. 
Inside the vote tally operation center in Los Angeles County on election night. 
Ballots are unpacked and distributed to tally machines. 
Election workers load ballots into automatic tally machines. 
Election workers load ballots into automatic tally machines. 
Mangers walk the floor of the Tally Operations Center monitoring progress. 
Election worker monitor tally progress. 
Election worker loads ballots into an automatic tally machine. 
Election worker loads ballots into an automatic tally machine. 
Election worker loads ballots into an automatic tally machine. 
Poll watchers monitor election works from viewing stations that surround the tally room. 
Election worker loads ballots into an automatic tally machine. 
Inside the vote Tally Operation Center in Los Angeles County on election night. 
Local and national media wait for results outside the Tally Operation Center in Los Angeles County.
Originally published in Bloomberg Businessweek.
During the 2020 election, the country’s largest vote by mail processing operation was in Pomona, California. Setup by Los Angeles Country to handle mail ballots sent this year to all of its 5.6 million registered voters, the operation employed hundreds of workers who worked around the clock receiving ballots from the Postal Service (as well as from official ballot drop boxes) and, in a race against time, prepare them for tallying on election night. Once the mail-ballots were processed, they were transported by LA Country Sherifs to the Country Tally Operations Center for counting.