1. Texas (1845): Texas was annexed by the United States after the Texas Revolution in 1836. It was admitted as the 28th state on December 29, 1845.
2. Iowa (1846): Iowa was admitted as the 29th state on December 28, 1846. It was part of the Louisiana Purchase territory and became a state after meeting population requirements.
3. Wisconsin (1848): Wisconsin was admitted as the 30th state on May 29, 1848. It was also part of the Louisiana Purchase and met the population requirements for statehood.
4. California (1850): California was admitted as the 31st state on September 9, 1850. It was acquired by the United States as part of the Mexican-American War.
5. Oregon (1859): Oregon was admitted as the 33rd state on February 14, 1859. It was part of the Oregon Territory, which was jointly occupied by the United States and Britain until 1846.
6. Kansas (1861): Kansas was admitted as the 34th state on January 29, 1861. It was part of the Kansas Territory and was involved in the "Bleeding Kansas" conflict over the issue of slavery.
7. Nevada (1864): Nevada was admitted as the 36th state on October 31, 1864. It was part of the Utah Territory and became a state during the Civil War due to its importance in silver mining.
8. Nebraska (1867): Nebraska was admitted as the 37th state on March 1, 1867. It was part of the Nebraska Territory and became a state after meeting population requirements.
9. Colorado (1876): Colorado was admitted as the 38th state on August 1, 1876. It was part of the Colorado Territory and became a state during the nation's centennial celebration.
10. North Dakota (1889): North Dakota was admitted as the 39th state on November 2, 1889, along with South Dakota. They were part of the Dakota Territory and were divided into separate states due to population differences.
11. South Dakota (1889): South Dakota was admitted as the 40th state on November 2, 1889, along with North Dakota. It was part of the Dakota Territory and was divided into separate states due to population differences.
These western states brought diverse landscapes, resources, and populations to the United States, contributing to the nation's growth and development during this period.