Since 1792, by the federal law of the U.S., the U.S. Congress permitted the
states to conduct their presidential elections (or otherwise to choose their
Electors) any time in a 34-day period before the first Wednesday of December,
which was the day set for the meeting of the Electors of the U.S. president
and vice-president (the Electoral College), in their respective states.
Because the harvest would have been completed (important in an agrarian society)
and the winter storms would not yet have begun in earnest (a plus in the days
before paved roads and snowplows), an election date in November was seen as
useful. However, in this arrangement the states that voted later could be influenced
by a candidate's victories in the states that voted earlier, a problem later
exacerbated by improved communications via train and telegraph. In close elections,
the states that voted last might well determine the outcome.
In 1845, auniform date for choosing presidential Electors was instituted by
the Congress. Many theories have been advanced as to why the Congress settled
on the first Tuesday after the first Monday in November. The actual reasons,
as shown in records of Congressional debate on the bill in December 1844, were
fairly prosaic. The bill initially set the national day for choosing presidential
Electors on "the first Tuesday in November," in years divisible by
four (1848, 1852, etc.).
However, it was pointed out that in some years the period between the first
Tuesday in November and the first Wednesday in December (when the Electoral
College met) would be more than 34 days, in violation of the existing Electoral
College law. So, the bill was amended to move the national date for choosing
presidential Electors forward to the Tuesday after the first Monday in November,
a date scheme already used in the state of New York.
The United States was largely an agrarian society in 1845. Farmers often needed
a full day to travel by horse-drawn vehicles to the county seat to vote. Tuesday
was established as election day because it did not interfere with the Biblical
Sabbath or with market day, which was on Wednesday in many towns.