The rules and procedures governing absentee or mail-in ballots vary widely from state to state. One key difference is when states are allowed to begin counting absentee or mail-in ballots.
Thirty-four states do not allow absentee/mail-in ballot counting to begin either until Election Day or after polls close.
Sixteen states allow officials to begin counting at least some absentee ballots before Election Day.
Seven of these states—Arizona, Colorado, Delaware, Montana, Nebraska, North Carolina, and Vermont—explicitly allow vote counting to begin before election day.
In nine of these states, statutes either do not specify when ballots may be counted or leave the decision to the discretion of local officials: Connecticut, Hawaii, Kansas, Kentucky, Louisiana, Ohio, Oklahoma, Oregon, and Utah.
Of the 16 states that allow absentee/mail-in ballots to be counted before election day, 10 voted for President Donald Trump (R) in the 2016 presidential election. The remaining six voted for Hillary Clinton (D).