The city of Columbia in South Carolina, the District of Columbia, and the Columbia River in the United States are all spelled with a but the nation of Colombia is correctly spelled with an “o”.
Colombia is in the northwestern corner of South America, where that continent joins Central America. Central America separates the Atlantic and Pacific oceans, and Colombia is the only country in South America with a shore on both oceans.
Some rivers in Colombia empty into the Caribbean Sea, some empty into the Pacific Ocean, and others empty into the Orinoco and Amazon rivers and eventually empty into the Atlantic!