Georgia's secretary of state on Friday certified the state's election results, which had Biden beating Trump by 12,670 votes out of about 5 million cast, or 0.25 per cent.
The final results certified by Secretary of State Brad Raffensperger had Biden with 2.47 million votes, President Donald Trump with 2.46 million votes and Libertarian Jo Jorgensen with 62,138.
The deadline for the counties to complete the audit is 11:59 p.m. Wednesday, ahead of the Friday deadline for state certification.
The ballots were found during a statewide, by-hand recount of votes in the U.S. presidential election, and were found in a county that swayed towards Donald Trump.
Election officials in Georgia's 159 counties are undertaking a hand tally of the presidential race that stems from an audit required by state law.