French aid, began in 1778 with a treaty came in the form of GUNS and other much needed supplies. These supplies proved vital in the American push to extend the war. French troops joined the war in 1778 in an attack on Newport, Rhode Island.
The Spanish joined in 1779 over a dispute with Britain over the Gibraltar. The Dutch joined following a dispute over terms of neutrality with the British.
The Spanish contributed mainly in the form of their powerful navy. They helped by causing the British to divert troops to other locations such as Gibraltar where they sieged it for 4 years though unsuccessfully. Spain also contributed gold and silver.
The Dutch also contributed in the form of their navy. Their contibutions were mainly in India. They, along with the French fought the British because all three had outposts there. The Dutch also contributed goods and money.
In 1780 the Armed Neutrality was formed by Catherine the Great, it included Denmark-Norway, Sweden, the Holy Roman Empire, Prussia, Portugal, and the Two Siciles.
In 1781, Admiral De Grasse and Rochambeau of the French helped defeat the British at the Battle of Yorktown. This was the most important French contribution.
Both France and Spain received territorial gains when America won its independence.
France gained Tobago, Saint Lucia, the Senegal River area, and fishing rights in Terra Nova. Spain gained Minorca and Florida.
Overall, the French made the biggest contributions to the Americans lending them money, men, and supplies. They also contributed ships and helped the Americans build up their meager navy. They made telling contributions on all fronts of the war. The Spanish helped with their navy and movey and contributed in the South and in Minorca. The Dutch contributed their navy, goods, and money and fought the British in India. Contributions by the Spanish and the Dutch have sadly been overlooked. The Spanish played a pretty crucial role in our independence. As is common, British stupidity is evident here. They forced both the Spanish and the Dutch to join up with the French in the cause of American Independence.