The District of Columbia is a federal district with an ethnically diverse population. In 2020, the District had a population of 689,545 people, with a resident density of 11,515 people per square mile. The District of Columbia had relatively few residents until the Civil War. The presence of the U.S. federal government in Washington has been instrumental in the city's later growth and development. Its role as the capital leads people to forget that approximately one-third of the District of Columbia's population was born in the city.