How did the Fourth of July become a national holiday?

 One party, the Democratic-Republicans, admired Jefferson and the Declaration. But the other party, the Federalists, thought the Declaration was too French and too anti-British, which went against their current policies.

By 1817, John Adams complained in a letter that America seemed uninterested in its past. But that would soon change.

After the War of 1812, the Federalist party began to come apart and the new parties of the 1820s and 1830s all considered themselves inheritors of Jefferson and the Democratic-Republicans. Printed copies of the Declaration began to circulate again, all with the date July 4, 1776, listed at the top. The deaths of Thomas Jefferson and John Adams on July 4, 1826, may even have helped to promote the idea of July 4 as an important date to be celebrated.

Celebrations of the Fourth of July became more common as the years went on and in 1870, almost a hundred years after the Declaration was written, Congress first declared July 4 to be a national holiday as part of a bill to officially recognize several holidays, including Christmas. Further legislation about national holidays, including July 4, was passed in 1939 and 1941.