The United Provinces of the Río de la Plata was a historical region in South America that existed from 1810 to 1862. It encompassed areas that are now part of Argentina, Uruguay, and parts of Bolivia and Paraguay. The provinces declared independence from Spanish rule during the May Revolution in 1810, leading to a series of conflicts known as the Argentine War of Independence. The government of the United Provinces was marked by political instability and civil wars, primarily between federalists and unitarians. In 1862, the provinces unified to form the modern nation of Argentina, establishing a more centralized government and paving the way for future development.