Admission of States to the Union: A Historical Reference Guide (CRS R47747)
Congressional Research Service, via Congress.gov · n.d. · Dates
Table 1 chronological list: Delaware December 7, 1787 through Hawaii August 21, 1959. Notes that six states joined without first being organized as a territory: California, Kentucky, Maine, Texas, Vermont, and West Virginia. Ohio is listed March 1, 1803.
https://www.congress.gov/crs-product/R47747 (opens in a new tab)
The Admission of Ohio as a State
US House of Representatives, History, Art & Archives · n.d. · Dates
Congress retroactively ratified Ohio’s constitution in 1953 and set admission as of March 1, 1803.
https://history.house.gov/HistoricalHighlight/Detail/36914 (opens in a new tab)
US Territory and Statehood Status by Decade, 1790–1960
US Census Bureau · n.d. · Dates
Year-of-statehood table for all 50 states. Years agree with the Atlas. Census here does not publish the day.
https://www.census.gov/dataviz/visualizations/048/508.php (opens in a new tab)
John Adams, Architect of American Government
Commonwealth of Massachusetts · n.d. · Original 13
Massachusetts Constitution of 1780, drafted principally by John Adams, remains in force. The Commonwealth calls it the oldest still-functioning written constitution in the world.
https://www.mass.gov/guides/john-adams-architect-of-american-government (opens in a new tab)
Researching the History of Amendments to the Massachusetts Constitution
State Library of Massachusetts · n.d. · Original 13
Ratified by the voters of the Commonwealth in 1780; still in effect, heavily amended.
Wyoming History — Equality Heritage
State of Wyoming · n.d. · West
Wyoming Territory’s 1869 act granted women the vote. Governor John A. Campbell signed it December 10, 1869. The franchise was already in force at 1890 statehood.
https://www.wyo.gov/about-wyoming/wyoming-history (opens in a new tab)
History of the Nebraska Unicameral
Nebraska Legislature · n.d. · West
Nebraska is the only US state with a single-house legislature. Voters adopted the change in 1934; the first unicameral session sat in 1937. Admission itself remains March 1, 1867.
https://nebraskalegislature.gov/about/history_unicameral.php (opens in a new tab)
Palace of the Governors, Santa Fe
National Park Service · n.d. · Last 48 and 50
Spanish seat of government in Santa Fe from 1610.
https://www.nps.gov/articles/000/new-mexico-palace-of-the-governors.htm (opens in a new tab)
Joint Resolution for Annexing the Hawaiian Islands (Newlands Resolution)
National Archives · 1898 · Last 48 and 50
Signed July 7, 1898. A joint resolution, not a ratified treaty. Hawaii was annexed as a territory, then admitted August 21, 1959. The same Archives page records the 1893 overthrow of Queen Liliʻuokalani and the Republic of Hawaii (1894).
Fort Sumter and Fort Moultrie National Historical Park
National Park Service · n.d. · Original 13
First shots of the Civil War: April 12, 1861, Charleston Harbor, South Carolina.
St. Augustine Town Plan Historic District
National Park Service · n.d. · Original 13
Founded 1565 by Pedro Menéndez de Avilés. NPS: oldest continuously occupied European settlement in the continental United States. Keys uses that continental limit — San Juan is older if territories are in the comparison.
Yellowstone National Park — Park Facts
National Park Service · n.d. · West
Established March 1, 1872. World’s first national park. Land: 96% Wyoming, 3% Montana, 1% Idaho.
https://www.nps.gov/yell/planyourvisit/parkfacts.htm (opens in a new tab)
Check for the Purchase of Alaska (1868)
National Archives · 1868 · Last 48 and 50
Treaty with Russia, March 30, 1867. Purchase price $7.2 million.
https://www.archives.gov/milestone-documents/check-for-the-purchase-of-alaska (opens in a new tab)
West Virginia Statehood, June 20, 1863
National Archives · n.d. · West
The only state formed by separating from a Confederate state during the Civil War. Lincoln proclaimed recognition as of June 20, 1863.
https://www.archives.gov/legislative/features/west-virginia (opens in a new tab)
Louisiana Purchase Treaty
National Archives · 1803 · Expansion
Signed April 30, 1803. The United States purchased 828,000 square miles from France for $15 million.
https://www.archives.gov/historical-docs/louisiana-purchase-treaty (opens in a new tab)
Missouri Compromise (1820)
National Archives · 1820 · Expansion
Admitted Maine as a free state and Missouri as a slave state together, so as not to upset the Senate balance. Also banned slavery north of 36°30′ in the remaining Louisiana Territory.
https://www.archives.gov/milestone-documents/missouri-compromise (opens in a new tab)
Compromise of 1850
National Archives · 1850 · Expansion
Five statutes in September 1850. California admitted as a free state (act approved September 9, 1850). CRS R47747 lists California among the six that skipped organized territorial status.
https://www.archives.gov/milestone-documents/compromise-of-1850 (opens in a new tab)
Kansas–Nebraska Act (1854)
National Archives · 1854 · Expansion
Approved May 30, 1854. Repealed the Missouri Compromise line in those territories. The ensuing violence is named Bleeding Kansas.
https://www.archives.gov/milestone-documents/kansas-nebraska-act (opens in a new tab)
Inaugural Balcony — Federal Hall National Memorial
National Park Service · n.d. · Original 13
April 30, 1789: Washington took the oath on the balcony of the original Federal Hall, 26 Wall Street, New York.
https://www.nps.gov/feha/learn/historyculture/inaugural-balcony.htm (opens in a new tab)
Acquisition of Florida: Treaty of Adams-Onís (1819)
US Department of State, Office of the Historian · n.d. · Expansion
Spain ceded East Florida and renounced West Florida. Signed 1819; ratified 1821 (Transcontinental Treaty).
https://history.state.gov/milestones/1801-1829/florida (opens in a new tab)
The Oregon Territory, 1846
US Department of State, Office of the Historian · n.d. · Expansion
Boundary with Britain settled at the 49th parallel to the Pacific, Vancouver Island excepted. Senate ratified June 18, 1846.
https://history.state.gov/milestones/1830-1860/oregon-territory (opens in a new tab)
The Treaty of Guadalupe Hidalgo
National Archives · n.d. · Expansion
Signed February 2, 1848. Mexico ceded Upper California and New Mexico and relinquished claims to Texas, recognizing the Rio Grande.
https://www.archives.gov/education/lessons/guadalupe-hidalgo (opens in a new tab)
Cockspur Island Before Fort Pulaski
National Park Service, Fort Pulaski National Monument · n.d. · Original 13
February 1733: English settlers led by Gen. James Edward Oglethorpe established Savannah. NPS: “the beginning of Georgia, the 13th American colony.” Atlas Georgia fact matches.
https://www.nps.gov/articles/000/cockspur-island-before-fort-pulaski.htm (opens in a new tab)
National Archives Celebrates the 145th Anniversary of Nevada Statehood
National Archives · 2009 · West
Lincoln proclaimed Nevada admitted “just eight days before the Presidential election,” hoping to ensure his re-election and like-minded Republicans in Congress.
https://www.archives.gov/press/press-releases/2009-37 (opens in a new tab)
“Rogue Island”: The last state to ratify the Constitution
National Archives, Pieces of History (Center for Legislative Archives) · 2015-05-18 · Original 13
Rhode Island refused to send delegates to the 1787 Convention. Last of the original 13 to ratify, May 29, 1790, by 34 to 32.
Enabling Act of 1889
United States Senate · 1889 · West
February 22, 1889: an act to divide Dakota into two states and enable North Dakota, South Dakota, Montana, and Washington to form constitutions and state governments.
https://www.senate.gov/artandhistory/history/common/image/EnablingAct1889.htm (opens in a new tab)
States in the Senate — North Dakota Timeline
United States Senate · n.d. · West
President Harrison signed the proclamation admitting North Dakota as the 39th state on November 2, 1889. Enabling legislation February 22, 1889. Matches the listing. This page does not record a paper-shuffle ceremony.
https://www.senate.gov/states/ND/timeline.htm (opens in a new tab)
States in the Senate — South Dakota Timeline
United States Senate · n.d. · West
Same day as North Dakota: November 2, 1889. South Dakota listed 40th. Twin admission from Dakota Territory matches the Atlas pairing. Signing-order folklore is not documented here.
https://www.senate.gov/states/SD/timeline.htm (opens in a new tab)
The Annexation of Texas, 1845–1848
US Department of State, Office of the Historian · n.d. · Expansion
Texas’ war of independence against Mexico, 1836. United States extended diplomatic recognition. Admitted December 29, 1845.
https://history.state.gov/milestones/1830-1860/texas-annexation (opens in a new tab)
The Battle of Bennington: An American Victory
National Park Service · n.d. · Early republic
The Hampshire Grants became the Republic of Vermont during the Revolution and remained an independent republic until 1791, then the fourteenth state. Ethan Allen’s Green Mountain Boys defended the Grants before the republic and took Fort Ticonderoga in 1775.
States in the Senate — Kentucky Timeline
United States Senate · n.d. · Early republic
June 1, 1792: 15th state. Congress consented to a new state out of the jurisdiction of an existing state (Article IV, section 3). CRS lists Kentucky among the six that skipped organized territorial status.
https://www.senate.gov/states/KY/timeline.htm (opens in a new tab)
David Campbell to George Washington, 10 April 1796
Founders Online, National Archives · 1796-04-10 · Early republic
Written from the Territory of the United States South of the River Ohio. The people of that territory were taking measures to become a member of the federal government by the name of the State of Tennessee.
https://founders.archives.gov/documents/Washington/05-20-02-0023 (opens in a new tab)
Mr. Ballif to Consul Spahr (Utah manifesto, 1890)
US Department of State, Office of the Historian (Foreign Relations, 1908) · 1908-09-16 · West
1890: Wilford Woodruff issued a manifesto prohibiting polygamous marriages. 1896: Utah admitted with a constitutional clause absolutely prohibiting polygamy. Territorial wait from 1850 is on the Compromise of 1850 page above.
https://history.state.gov/historicaldocuments/frus1908/d297 (opens in a new tab)
States in the Senate — Colorado Timeline
United States Senate · n.d. · West
August 1, 1876: Grant admitted Colorado as the 38th state. “Statehood occurred on the 100th anniversary of the Declaration of Independence thereby providing the nickname ‘The Centennial State.’” Atlas fact matches.
https://www.senate.gov/states/CO/timeline.htm (opens in a new tab)
Oklahoma Statehood, November 16, 1907
National Archives · n.d. · Last 48 and 50
Congress insisted Indian Territory and Oklahoma Territory enter as one state. Enabling Act of June 16, 1906; Roosevelt’s proclamation November 16, 1907, 46th state.
https://www.archives.gov/legislative/features/oklahoma (opens in a new tab)
States in the Senate — Arizona Timeline
United States Senate · n.d. · Last 48 and 50
February 14, 1912: Arizona became the 48th state. CRS Table 1: Alaska 49th and Hawaii 50th follow in 1959.
https://www.senate.gov/states/AZ/timeline.htm (opens in a new tab)
The Founding Fathers: Virginia
National Archives · n.d. · Original 13
Washington born at Wakefield Plantation, Virginia; the Electoral College chose him as the first President. Madison born King George County, Virginia; succeeded Jefferson as President in 1809. Two of the four Virginia names in the Atlas fact.
https://www.archives.gov/founding-docs/founding-fathers-virginia (opens in a new tab)
Thomas Jefferson — Jefferson Memorial
National Park Service, Thomas Jefferson Memorial · n.d. · Original 13
Born 1743 at Shadwell, Goochland (present Albemarle) County, Virginia. Captured the presidency (third President).
https://www.nps.gov/thje/learn/historyculture/thjebio.htm (opens in a new tab)
James Monroe — Star-Spangled Banner National Historic Trail
National Park Service · n.d. · Original 13
Born in Westmoreland County, Virginia. Elected the fifth president, 1817–1825. With Washington, Jefferson, and Madison (pages above), four of the first five presidents were Virginians. John Adams is the exception.
https://www.nps.gov/stsp/learn/historyculture/james-monroe.htm (opens in a new tab)
The Lincoln Home
National Park Service, Lincoln Home National Historic Site · n.d. · Early republic
Abraham Lincoln came of age as a private citizen in Springfield, Illinois. The family bought the home in May 1844 and lived there until leaving for the White House in February 1861. The park’s home page calls it “the only home that Abraham Lincoln ever owned.” Atlas: Lincoln’s adopted home.
https://www.nps.gov/liho/the-lincoln-home.htm (opens in a new tab)
States in the Senate — Mississippi Timeline
United States Senate · n.d. · Early republic
Mississippi Territory organized April 7, 1798 from land ceded from Georgia and South Carolina. Admitted December 10, 1817 as the 20th state. Matches the 1798/Georgia trail.
https://www.senate.gov/states/MS/timeline.htm (opens in a new tab)
States in the Senate — Alabama Timeline
United States Senate · n.d. · Early republic
March 3, 1817: Mississippi Territory divided into the state of Mississippi and the Territory of Alabama. Alabama admitted December 14, 1819 as the 22nd state.
https://www.senate.gov/states/AL/timeline.htm (opens in a new tab)
States in the Senate — Idaho Timeline
United States Senate · n.d. · West
July 3, 1890: Idaho admitted as the 43rd state. July 4 is the Declaration date on the Archives page in Founding.
https://www.senate.gov/states/ID/timeline.htm (opens in a new tab)
Washington State Nickname
Washington State Legislature · n.d. · West
November 11, 1889: Washington became the 42nd state. “It is the only state in the Union that is named for a president.” Atlas Washington fact matches.
Cessions of Land by Indigenous Peoples in the State of Indiana
National Park Service, Indiana Dunes · n.d. · Early republic
“The name ‘Indiana’ means ‘Land of the Indians’ and was named for the state’s first inhabitants.” The Indiana Historical Bureau dates the name to a 1768 tract south of the Ohio, given to Indiana Territory in 1800.
The Naming of Indiana
Indiana Historical Bureau (IN.gov) · n.d. · Early republic
In 1768 the Six Nations reserved a tract south of the Ohio River for a Philadelphia company, and the proprietors named it Indiana. The 1800 Act names the territory; this page is the Bureau's account of the name.
Act Creating Indiana Territory (1800)
Indiana Historical Bureau (IN.gov) · 1800 · Early republic
Approved May 7, 1800. Western remainder of the Northwest Territory “shall … be called the Indiana Territory.” Atlas: admitted from Indiana Territory. Matches the territorial trail.
States in the Senate — Indiana Timeline
United States Senate · n.d. · Early republic
December 11, 1816: Indiana became the 19th state.
https://www.senate.gov/states/IN/timeline.htm (opens in a new tab)
The Toledo War
Michigan Department of Military and Veterans Affairs · n.d. · Expansion
Congress held Michigan statehood until it accepted Ohio’s claim to the Toledo Strip. Admitted 26th on January 26, 1837, without the Strip; gained the western three-quarters of the Upper Peninsula as compensation. The same page: Territorial Governor Stevens T. Mason led a 250-person group of volunteers toward Toledo; Michigan’s militia arrested some Ohio officials, captured nine surveyors, and fired a few shots over the heads of others.
The War that Sparked a Sports Rivalry
American Battlefield Trust · n.d. · Expansion
Fifty members of the Michigan militia attacked Ohio surveyors on April 26, 1835, at the fight the article calls the Battle of Phillip's Corners, and captured nine of them.
https://www.battlefields.org/learn/articles/war-sparked-sports-rivalry (opens in a new tab)
Marietta: The Northwest a new territory
National Park Service, George Rogers Clark National Historical Park · n.d. · Expansion
Northwest Ordinance: no more than five and no less than three states. Those five: Indiana, Ohio, Illinois, Michigan, and Wisconsin. Minnesota later took a remaining northern slice — that is why ShadowPoint does not say Wisconsin was the last land carved from the old Northwest.
https://www.nps.gov/gero/learn/historyculture/marietta.htm (opens in a new tab)
States in the Senate — Wisconsin Timeline
United States Senate · n.d. · Expansion
May 29, 1848: Wisconsin admitted as the 30th state. Last of the five Ordinance states by date (Ohio 1803, Indiana 1816, Illinois 1818, Michigan 1837, Wisconsin 1848).
https://www.senate.gov/states/WI/timeline.htm (opens in a new tab)
States in the Senate — Minnesota Timeline
United States Senate · n.d. · Expansion
March 3, 1849: Congress established Minnesota Territory; slavery prohibited. May 11, 1858: admitted as the 32nd state.
https://www.senate.gov/states/MN/timeline.htm (opens in a new tab)
Rush-Bagot Pact of 1817 and Convention of 1818
US Department of State, Office of the Historian · n.d. · Expansion
Negotiators made present-day Angle Inlet, Minnesota the end point of the 1783 border. The Convention of 1818 ran the line south from Angle Inlet to the 49th parallel, then west to the Rockies. That dogleg is the Northwest Angle.
https://history.state.gov/milestones/1801-1829/rush-bagot (opens in a new tab)
States in the Senate — Arkansas Timeline
United States Senate · n.d. · Expansion
Louisiana Purchase of April 30, 1803 included the land of present Arkansas. March 2, 1819: territorial government for the southern part of Missouri Territory (Arkansas Territory). June 15, 1836: 25th state.
https://www.senate.gov/states/AR/timeline.htm (opens in a new tab)
States in the Senate — Iowa Timeline
United States Senate · n.d. · Expansion
December 28, 1846: Iowa entered as the 29th state. The Iowa Territory organic act was not opened on this page.
https://www.senate.gov/states/IA/timeline.htm (opens in a new tab)
An Act to divide the Territory of Wisconsin and to establish the Territorial Government of Iowa, 5 Stat. 235
US Government Publishing Office (Statutes at Large) · 1838 · Expansion
Act of June 12, 1838, ch. 96. Effective July 3, 1838: Wisconsin Territory west of the Mississippi became the Territory of Iowa. Matches the organic act.
https://www.govinfo.gov/content/pkg/STATUTE-5/pdf/STATUTE-5-Pg235.pdf (opens in a new tab)
An Act for the admission of the States of Iowa and Florida into the Union, 5 Stat. 742
US Government Publishing Office (Statutes at Large) · 1845-03-03 · Expansion
Approved March 3, 1845. One act for both territories. CRS: Florida’s admission was immediate; Iowa’s followed December 28, 1846, after a border dispute. The enrolled act does not call either state free or slave.
https://www.govinfo.gov/content/pkg/STATUTE-5/pdf/STATUTE-5-Pg742-2.pdf (opens in a new tab)
GPO Style Manual (2016) — State populations and their capitals
US Government Publishing Office · 2016 · Seats
Chapter 17 table, Census estimates as of July 1, 2015. All 50 Atlas state seats match (Minnesota printed St. Paul; Atlas writes Saint Paul). Chapter 18 lists territorial seats: San Juan, Agana, Pago Pago, Charlotte Amalie, Saipan, and Washington for the District. GPO still prints Guam as Agana, the older English form of Hagåtña, which the Atlas uses.
States in the Senate — Oregon Timeline
United States Senate · n.d. · Expansion
February 14, 1859: Oregon became the 33rd state. That date is February 14. Oregon Territory organized August 14, 1848.
https://www.senate.gov/states/OR/timeline.htm (opens in a new tab)
States in the Senate — Kansas Timeline
United States Senate · n.d. · Expansion
Wyandot free-state constitution, 1859. President signed January 29, 1861; Kansas the 34th state. Fort Sumter (already cited) is April 12, 1861 — weeks later. Matches the admission date.
https://www.senate.gov/states/KS/timeline.htm (opens in a new tab)
Mount Rushmore National Memorial
National Park Service · n.d. · West
The memorial sits in the Black Hills of South Dakota. Mailing address: Keystone, SD. Keys: Mount Rushmore is in South Dakota, near Keystone.
Homesteading — Florissant Fossil Beds
National Park Service, Florissant Fossil Beds National Monument · n.d. · West
“The Pike’s Peak or Bust Gold Rush of 1858 brought thousands of people to Colorado.” They settled mining camps throughout the mountains. Keys: 1858–59 Pikes Peak rush; Atlas Colorado militia: after the Pikes Peak rush. Matches the slogan and the 1858 Colorado trail.
https://www.nps.gov/flfo/learn/historyculture/homesteading.htm (opens in a new tab)
Nevada and the Civil War
Nevada State Library, Archives and Public Records · 2025-10-30 · West
Nevada became the 36th state on October 31, 1864. The Civil War legacy lives on in the nickname “The Battle Born State.” In 1863 the territory recruited six cavalry and three infantry companies, mustered as Nevada Volunteers.
https://nsla.nv.gov/blogs/system/nevada-in-the-civil-war (opens in a new tab)
NRS 235.020 — State flag
Nevada Legislature · n.d. · West
The official flag’s scroll bears the words “Battle Born.” Keys: the nickname refers to Civil War admission, not a battlefield in Nevada.
https://www.leg.state.nv.us/nrs/nrs-235.html (opens in a new tab)