Why were new states such as Colorado and the Dakotas admitted to the Union in the late 1800s?

New states like Colorado and the Dakotas were admitted to the Union in the late 1800s primarily due to westward expansion and the need to integrate new territories following the Civil War. The discovery of minerals, such as gold and silver, spurred economic growth and population influx, leading to statehood. Additionally, the government aimed to promote settlement and development in the West, reflecting the ideology of Manifest Destiny. These factors combined made it politically and economically advantageous to admit new states.