Was st Charles ever the capital of Missouri?
Yes, it was a temporary capital.
Missouri became a state in 1820. Prior to that, the capital of the Missouri Territory was St. Louis, MO. When Missouri became a state, the capital was moved to St. Charles, MO. In 1826, Jefferson City became the capital of Missouri. During the Civil War, the Confederate capital of Missouri was re-located to Marshall, TX.
The capital of Missouri as a territory was St. Louis, and it was the de facto capital when Missouri became a state in August, 1821. However, the city of St. Charles, slightly NW on the Missouri River, can be said to be the first actual state capital: it served as the temporary capital from 1821 to 1826, while the new capital at Jefferson City was being built, farther inland on the Missouri.
Missouri had had three state capitals. In 1812, when the Missouri Territory was established, St. Charles was chosen as the capital, and remained the capital until 1821. In 1821, the capital was moved to Lohman's Landing. Later, Lohman's Landing was changed to Jefferson City, which is the current capital of Missouri.
The first state capital was in St. Charles, Missouri, from 1821 to 1826. The territorial capital (from the Louisiana Territory) was in St. Louis, but in 1821 the southeastern part of the territory became the state of Missouri. On gaining statehood, a new capital was built at Jefferson City, then called Lohman's Landing. The city was named for Thomas Jefferson.