I'm not completely convinced about the validity of such charts, or of any chart representing an inanimate entity. If there is going to be a chart to represent a country though, it ought to reflect the "feel" of the country in question, even if placements don't coincide exactly with historically important events. So, concentrating only on national characteristics, what outstanding and necessary features would I look for in a chart for the USA?
1. First: Aquarius and/or Uranus ought to be emphasised. The birth of the USA was an Aquarian/Uranian event. The establishment of the Republic is sometimes referred to as "The Great Experiment" - an effort to provide government of the people, by the people, for the people. Whether or not it has worked out as planned, it was a very Aquarian/Uranian vision and proposition. From days of the early pioneers, people of the USA have displayed a determination to create change (Uranus) of one kind or another in their own lives or the lives of others, not always for the good, it has to be said! Aquarius and Uranus are not necessarily forces for good.
2. Sagittarius/Jupiter should have fairly prominent placing. Excess, over-indulgence, "bigness", exaggeration, hyperbole are all recognisable in the overall character of this country, to me as a relative outsider, anyway. Mustn't forget religion, which is also the province of Jupiter/Sagittarius. Many of the original settlers were fleeing their own countries to find religious freedom; religion has been, and still is, for good or ill, an important part of this nation's character.
3. Leo ought to feature in the chart. Leo leads, and the USA thinks of itself as "world leader".
4. Mars should feature: military might, and the will to fight, has been present from the Revolutionary War which spawned the USA, to current debacles in the Middle East, with many between.
All the 4 July 1776 charts have, to my mind, too much emphasis on Cancer (their Sun's position). The same applies to the 2 July chart, which I'd considered a reasonable choice in the past. I really don't see the USA's character in any way Cancerian.
The Signing of the Constitution chart has Sun in Virgo, also inappropriate for the USA, in my view.
The best match I've found is the David Solte 1777 chart:
"David Solte's Presentation of the U.S. chart, data given in San Diego Astrological Society "The Uranian," May 1993, time rectified. He used the minutes of the Continental Congress to narrow down the passage of the Articles of Confederation to a few hours between 11:00 am and 2:00 pm on Nov. 15, 1777, when they were meeting in York, PA. Solte then rectified the chart to 12:46 pm Local Mean Time for the date and time when the Articles of Confederation became effective. The Declaration of Independence had declared that America was a separate entity from Great Britain, but it was not until the Confederation was established that the U.S. became a group of states united under one government.
Quite a few astrologers find that this chart works well for following the fortunes of the US government and the nation as a whole."
(Chart copied from Astrodatabank).
No single chart exactly fits my own opinion of a national personality chart for the USA. David Solte's 1777 chart comes near.
[Edited version of a 2008 post]