On January 23, 1845, the 28th US Congress passed "An act to establish a uniform time for holding elections for electors of President and Vice President in all the States of the Union." The act selected "the Tuesday after the first Monday in November" as the day on which all states must appoint electors. However, if a state fails to appoint electors by that day, then "the electors may be appointed on a subsequent day in such manner as the State shall by law provide." This standardization greatly increased the speed of Presidential elections; the previous election of 1844 lasted from November 1-December 4. From 1848 onward, every Presidential election has been held on this date.

Citations

Presidential Election Day Act ch. 1, {{USStat, 5, 721 1845 in American politics 1845 in American law Presidency of the United States Acts_of_the_28th_United_States_Congress