A total of 235 men were elected to the Electoral College, but three—one each from Mississippi, Pennsylvania, and Tennessee—did not cast their ballots.[3] At least two, Melchior Rahm and Duncan Stewart, had died before their state's electors voted; the disposition of the third is unclear.
In addition, the status of the three electors from Missouri was a matter of dispute. Congress had passed an enabling act directing Missouri to organize a state government and that "the said state, when formed, shall be admitted into the Union."[4] The dispute was over whether Missouri's new state constitution fulfilled the requirements. In the end, two official vote totals were announced by Congress, one counting Missouri's votes and one not, with neither declared the canonical result — the source of debates over whether Monroe won 231 or 228 electoral votes.[5] Missouri was not officially admitted as a state until August 10, 1821.
All four of Delaware's electors voted Monroe for president. For vice president, however, all four voted for Delaware FederalistDaniel Rodney, the only votes he received.[1][2]
All 11 of Maryland's electors voted Monroe for president. Ten voted Tompkins for vice president, but James Forrest cast his ballot for Maryland FederalistRobert Goodloe Harper.[1][2]
All 15 of Massachusetts's electors voted Monroe for president. Seven of the 15 voted for Tompkins for vice president, but eight voted instead for New Jersey FederalistRichard Stockton, the only votes he received. No known record indicates which electors voted for each candidate.[1][2]
Two of Mississippi's 3 electors voted for Monroe and Tompkins. Elector Duncan Stewart died on November 26, 1820, before casting his ballot.[1][2][6][7]
All 3 of Missouri's electors voted for Monroe and Tompkins, though whether they should be counted—Missouri would not be formally admitted as a state for several more months—was an unsettled matter of dispute.[1][2]
All 25 Pennsylvania electors were pledged to Monroe and Tompkins, but only 24 ended up casting ballots. Former state senator Melchior Rahm was chosen as an elector, but he died on the day Pennsylvania electors were scheduled to vote, October 31, 1820.[1][2]
Seven of Tennessee's 8 electors voted for Monroe and Tompkins. For reasons that remain unclear, no elector voted for the state's fourth elector district.[1][2][8][9]