Colombia effectively achieved its independence from Spain by 1819, and the country was recognized by the United States in 1822, when President Monroe received a Colombian diplomatic representative in Washington. The United States established a diplomatic mission in Colombia in 1823. At that time, the Colombian federation included the territory of the present-day republics of Colombia, Ecuador, Venezuela, and Panama. U.S. relations with the government in Bogotá were not interrupted when Ecuador and Venezuela left the federation in 1830. From 1830 to 1856, the country was known as New Granada, and from 1856 to 1863, it was known as the Grenadine Confederation. The country became the United States of Colombia in 1863, and it changed its name to the Republic of Colombia in 1886. Panama separated from Colombia in 1903.
Source, United States, Department of State, Office of the Historian