Spain and United States signed this treaty.
A formal agreement between two countries is called a treaty or a pact.
The Pinckney's Treaty was the treaty that established friendly relations between the United States and Spain and defined the boundaries between the United States and the Spanish colonies. It was signed in October 1795.
Pinckney's Treaty was a treaty signed between the United States and Spain. It defined the boundaries between the United States and the Spanish colonies and guaranteed the United States navigation rights on the Mississippi River.
An alliance or agreement between two countries :)
The Oregon Treaty
Because of the conflict between the countries
Portugal and Spain signed the Treaty of Tordesillas, which had to do with newly found lands, and how the two countries would divide that land between them. Both countries ratified the treaty in 1494.
a treaty is an agreement between two or more nations.
You may be thinking of the Antarctic Treaty.
a formal agreement between the governments of two or more countries
treaty