Whenever the Animaniacs (1993) "travel through history", many obviously humorous inaccuracies are to be expected; it's not a documentary. However, some examples are either not revealed in a humorous fashion, or are so subtle that most viewers may miss them, so these are specifically counted as goofs.
The Boston Tea Party happened on 16 December 1773, not 1775 as the caption indicates. It was a harsh, snow-covered Massachussetts winter, contrary to what is depicted in this short.
Benjamin Franklin "electricity kite" experiment (1752) and the Declaration of Independence (1776) happened 24 years apart, not simultaneously as shown here.
The French people were not "revolting" against their own rulers in 1776. They only started doing so in 1789.
In the Presidents Song, Yakko, Wakko and Dot say that "In 1913 Woodrow Wilson takes us into World War One." WWI began in 1914, Wilson first took America into war in 1917.