List of U.S. states by date of admission to the Union in the context of "Illinois"

Utah is a landlocked state in the Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northeast, Idaho to the north, and Nevada to the west. In comparison to all the U.S. states and territories, Utah, with a population of just over three million, is the 13th-largest by area, the 30th-most populous, and the 11th-least densely populated. Urban development is mostly concentrated in two regions: the Wasatch Front in the north-central part of the state, which includes the state capital, Salt Lake City, and is home to roughly two-thirds of the population; and Washington County in the southwest, which has approximately 180,000 residents. Most of the western half of Utah lies in the Great Basin.

Utah has been inhabited for thousands of years by various indigenous groups, such as the ancient Puebloans, the Navajo, and the Ute. The first Europeans to arrive – in the mid-16th century – were the Spanish. Because of the region's challenging geography and harsh climate, it only became a peripheral part of New Spain (and later of Mexico). Even while it was Mexican territory, many of the Utah region's earliest European settlers were from the United States; notable among these were Mormons who were fleeing marginalization and persecution in the United States and arrived via the so-called Mormon Trail. In 1848, after the Mexican–American War, the region was annexed by the U.S., becoming part of the Utah Territory, which included what later became Colorado and Nevada. Disputes between the dominant Mormon community and the federal government delayed Utah's admission as a state: in 1896, after it agreed to outlaw polygamy, it was admitted as the 45th state.

Florida (/ˈflɒrɪdə/ FLORR-ih-də; Spanish: [floˈɾiða] ) is a state in the Southeastern and South Atlanticregions of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia to the north, the Atlantic Ocean to the east, the Straits of Florida to the south, and The Bahamas to the southeast. About two-thirds of Florida occupies a peninsula between the Gulf of Mexico and the Atlantic Ocean. It has the longest coastline in the contiguous United States, spanning approximately 1,350 miles (2,170 km), not including its many barrier islands. It is the only state that borders both the Gulf of Mexico and the Atlantic Ocean. With a population of over 23 million, it is the third-most populous state in the United States and ranks seventh in population density as of 2020. Florida spans 65,758 square miles (170,310 km), ranking 22nd in area among the states. The Miami metropolitan area, anchored by the cities of Miami, Fort Lauderdale, and West Palm Beach, is the state's largest metropolitan area, with a population of 6.138 million; the most populous city is Jacksonville. Florida's other major population centers include Tampa Bay, Orlando, Cape Coral, and the state capital of Tallahassee.

Various Native American groups have inhabited Florida for at least 14,000 years. In 1513, Spanish explorer Juan Ponce de León became the first documented European to make landfall in the region and named it La Florida (Spanish for "land of flowers"; [la floˈɾiða]), giving the territory its present name. Spain subsequently incorporated Florida into the Spanish Empire in the early 16th century. In 1565, it founded St. Augustine, the oldest continuously inhabited European-established settlement in the continental United States. The region was frequently coveted and attacked by Great Britain throughout the 18th century. Britain briefly gained control of Florida in 1763, but Spain recovered it in 1783 following the British defeat in the American Revolutionary War. Florida remained under Spanish rule until it was ceded to the United States in 1821, in exchange for U.S. recognition of Spanish sovereignty in Texas and the resolution of the border dispute along the Sabine River. Florida was admitted as the 27th state on March 3, 1845, and was the principal location of the Seminole Wars (1816–1858), the longest and most extensive of the American Indian Wars. The state seceded from the Union on January 10, 1861, becoming one of the seven original Confederate States, and was readmitted to the Union after the Civil War on June 25, 1868.

The Republic of Texas was the only state to enter by treaty into the United States and admitted to the Union as the 28th state on December 29, 1845.

The Republic of Texas declared independence from the Republic of Mexico on March 2, 1836. It applied for annexation to the United States the same year, but was rejected by the United States secretary of state, John Forsyth, under President Andrew Jackson. At that time, the majority of the Texian population favored the annexation of the Republic by the United States. The leadership of both major U.S. political parties (the Democrats and the Whigs) opposed the introduction of Texas – a vast slave-holding region – into the volatile political climate of the pro- and anti-slavery sectional controversies in Congress. Moreover, they wished to avoid a war with Mexico, whose government had outlawed slavery and refused to acknowledge the sovereignty of its rebellious northern province. With Texas's economic fortunes declining by the early 1840s, the president of the Texas Republic, Sam Houston, arranged talks with Mexico to explore the possibility of securing official recognition of independence, with the United Kingdom mediating.

The California gold rush (1848–1855) was a gold rush in California, which began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people from the rest of the United States and abroad to California, which had recently been conquered from Mexico. The sudden influx of gold into the money supply reinvigorated the American economy; the sudden population increase allowed California to grow rapidly into statehood in the Compromise of 1850. The gold rush had severe effects on Native Californians and accelerated the Native American population's decline from disease, starvation, and the California genocide.

The effects of the gold rush were substantial. Whole indigenous societies were attacked and pushed off their lands by the gold-seekers, nicknamed "forty-niners" (referring to 1849, the peak year for gold rush immigration). Outside of California, the first to arrive were from Oregon, Hawaii, and Latin America in late 1848. Of the approximately 300,000 people who came to California during the gold rush, about half arrived by sea and half came overland on the California Trail and the California Road; forty-niners often faced substantial hardships on the trip. While most of the newly arrived were Americans, the gold rush attracted thousands from Latin America, Europe, Australia, and China. Agriculture and ranching expanded throughout the state to meet the needs of the settlers. San Francisco grew from a small settlement of about 200 residents in 1846 to a boomtown of about 36,000 by 1852. Roads, churches, schools and other towns were built throughout California. In 1849, a state constitution was written. The new constitution was adopted by referendum vote; the future state's interim first governor and legislature were chosen. In September 1850, California achieved statehood.

Idaho (/ˈaɪdəhoʊ/ ) is a landlocked state in the Pacific Northwest and Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west; the state shares a small portion of the Canada–United States border to the north with the Canadian province of British Columbia. Idaho's state capital and largest city is Boise. With an area of 83,569 square miles (216,440 km), Idaho is the 14th-largest state by land area. The state has a population of approximately two million people; it ranks as the 13th-least populous and the seventh-least densely populated of the 50 U.S. states.

For thousands of years, and prior to European colonization, Idaho had been inhabited by natives. In the early 19th century, Idaho was considered part of the Oregon Country, an area which was disputed between the U.S. and the British Empire. Idaho officially became a U.S. territory with the signing of the Oregon Treaty of 1846, but a separate Idaho Territory was not organized until 1863, instead being included for periods in Oregon Territory and Washington Territory. The state was eventually admitted to the Union on July 3, 1890, becoming the 43rd state.

Mississippi (/ˌmɪsɪˈsɪpi/ MISS-iss-IP-ee) is a state in the Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the southwest, and Arkansas to the northwest. Mississippi's western boundary is largely defined by the Mississippi River, or its historical course. Mississippi is the 32nd largest by area and 35th-most populous of the 50 U.S. states and has the lowest per-capita income. Jackson is both the state's capital and largest city. Greater Jackson is the state's most populous metropolitan area, with a population of 591,978 in 2020. Other major cities include Gulfport, Southaven, Hattiesburg, Biloxi, Olive Branch, Tupelo, Meridian, and Greenville.

The state's history traces back to around 9500 BC with the arrival of Paleo-Indians, evolving through periods marked by the development of agricultural societies, rise of the Mound Builders, and flourishing of the Mississippian culture. European exploration began with the Spanish in the 16th century, followed by French colonization in the 17th century. Mississippi's strategic location along the Mississippi River made it a site of significant economic and strategic importance, especially during the era of cotton plantation agriculture, which led to its wealth pre-Civil War, but entrenched slavery and racial segregation. On December 10, 1817, Mississippi became the 20th state admitted to the Union. By 1860, Mississippi was the nation's top cotton-producing state and slaves accounted for 55% of the state population. Mississippi declared its secession from the Union on January 9, 1861, and was one of the seven original Confederate States, which constituted the largest slaveholding states in the nation. Following the Civil War, it was restored to the Union on February 23, 1870. Mississippi's political and social landscape was dramatically shaped by the Civil War, Reconstruction era, and civil rights movement, with the state playing a pivotal role in the struggle for civil rights. From the Reconstruction era to the 1960s, Mississippi was dominated by socially conservative and segregationist Southern Democrats dedicated to upholding white supremacy.