According to Wikipedia, in 1781,"the state" of Massachusetts became the first to recognize July 4 as a state celebration. Almost right. Technically, we're a Commonwealth. (The difference apparently is in name only but, me, I only live in such entities, apparently - born in the Commonwealth of Pennsylvania, have lived my whole adult life in Mass.)
There are no doubt a zillion blog posts about Independence Day in the US, what it means, why it's important, and how America is this, that, and the other thing, good, bad, blah-buh-dee-blah-blah.
I have only this to say: Founding a country is a really big deal. A HUGE deal. Now think about all the countries that have been founded. The imagination of our species, the desire for independence, the drive to start anew, the imperative of freedom, all testament to the brilliance of humanity.