3 Views 0 Comments Shares

Top 10 Last States to Join the United States

By Dhiraj Sharma · Published November 12, 2026

Listen to this article Free TTS Play using your browser's built-in text-to-speech

Editorial admission-date step ladder in constitution ivory and seal navy, with generic date blocks and no seals.

The last ten states to join the United States were admitted between 1889 and 1959, and their official admission dates are a matter of federal law. This list uses the effective admission date set by Congress, or by a presidential proclamation that an admission law required, as compiled in the Library of Congress CRS guide and in standard official tables ^[1]^[2].

The ten states here are numbers 41 through 50. They fall into three clusters: four northwestern admissions in November 1889, Idaho and Wyoming in July 1890, then a slower sequence from Utah in 1896 to Hawaii in 1959. North Dakota and South Dakota, both admitted on 2 November 1889 as the 39th and 40th states, sit just outside this ten and are mentioned only to fix the starting point ^[1]^[3]. In a few cases the president signed an admission bill on one day and the law or a required proclamation made statehood effective on another; this article follows the effective date, which is the date official tables use when they number the states ^[1]^[2].

Key Facts

For the original 13 states, "admission" means ratification of the Constitution. For every state below, the date is the day admission became effective. Rank 1 is the most recent state. The CRS guide is the primary date list used here because it is a congressional reference, not a souvenir calendar, and because it notes the occasional difference between a signature date and an effective date ^[1]. Where a territory had to vote on a statehood act, as Hawaii did, the official day is still the date admission took effect, not the date of the referendum ^[4].

Last States Admitted at a Glance

Rank	State	Admission date	State number	Formed from
1	Hawaii	21 August 1959	50th	Territory of Hawaii
2	Alaska	3 January 1959	49th	Territory of Alaska
3	Arizona	14 February 1912	48th	Arizona Territory
4	New Mexico	6 January 1912	47th	New Mexico Territory
5	Oklahoma	16 November 1907	46th	Oklahoma Territory and Indian Territory
6	Utah	4 January 1896	45th	Utah Territory
7	Wyoming	10 July 1890	44th	Wyoming Territory
8	Idaho	3 July 1890	43rd	Idaho Territory
9	Washington	11 November 1889	42nd	Washington Territory
10	Montana	8 November 1889	41st	Montana Territory

1. Hawaii

Hawaii is the 50th state and the most recent admission. It became a state on 21 August 1959, after Congress passed the Hawaii Admission Act and voters in the territory approved statehood ^[1]^[4]. The new state was formed from the Territory of Hawaii, itself created after the overthrow of the Hawaiian Kingdom and annexation at the end of the nineteenth century.

It is first on this list because no state has been admitted since. That fact has been stable for more than six decades and is why the flag has 50 stars ^[1]. A 2026 reader should treat 21 August 1959 as the official date, not the date of a later ceremonial event.

Hawaii is also the only state in this ten that is not on the North American mainland. The admission completed the present map of 50 states, including a Pacific island chain that had been a territory since 1900 ^[4].

2. Alaska

Alaska was admitted on 3 January 1959, as the 49th state, under the Alaska Statehood Act of 7 July 1958 and Presidential Proclamation 3269, which made admission effective on that January date ^[1]^[5]. The land had been purchased from Russia in 1867 and organised as a territory in 1912.

It is second only because Hawaii followed later the same year. Alaska is by far the largest state by area, a fact treated in Finepedia's list of the largest states, but size was not the legal test for admission ^[2]^[5].

The seven-month gap between Alaska and Hawaii in 1959 is the last time two states joined in the same calendar year. Before that, the closest pairing in this ten is New Mexico and Arizona in January and February 1912 ^[1].

3. Arizona

Arizona was admitted on 14 February 1912, as the 48th state, completing the contiguous lower 48 ^[1]^[3]. It was formed from Arizona Territory, land that had come to the United States through the Treaty of Guadalupe Hidalgo and the Gadsden Purchase.

It is third as the last of the contiguous admissions. After Arizona, the country waited 47 years for Alaska. That long pause is the main break in the modern admission calendar ^[1].

The Valentine's Day date is the official effective date, and it is the one used in congressional and official tables. Enabling legislation and a state constitution had come earlier; the date that counts for this list is the day admission took effect ^[1]^[2].

4. New Mexico

New Mexico was admitted on 6 January 1912, as the 47th state, five weeks before Arizona ^[1]^[3]. Congress had passed an admission act in 1911; a presidential proclamation then set the January date. The state was formed from New Mexico Territory, organised in 1850 from land ceded after the Mexican-American War.

It is fourth because it is the later of the two 1912 admissions only in state number, not in "lastness": Arizona is more recent. Together the two admissions finished the contiguous map from the Atlantic to the Pacific ^[1].

New Mexico's territorial period was long. The 1912 date is the end of that period, not the beginning of Euro-American or Indigenous history in the region, which is far older ^[3].

5. Oklahoma

Oklahoma was admitted on 16 November 1907, as the 46th state, formed by combining Oklahoma Territory and Indian Territory ^[1]^[2]. That combination is the distinctive legal fact of this admission: two neighbouring territorial jurisdictions were admitted as one state.

It is fifth as the last admission of the first decade of the twentieth century, and as the last state added before New Mexico and Arizona completed the Southwest. The 1907 date is the official effective date used in the CRS table ^[1].

The land and the political history behind the two territories are a longer story than this list can carry. The ranking question is only when the state entered the Union ^[2].

6. Utah

Utah was admitted on 4 January 1896, as the 45th state, after a long territorial period that began in 1850 ^[1]^[3]. Admission followed years of negotiation over the territorial government and the conditions Congress set for statehood.

It is sixth because more than a decade separates Utah from Oklahoma, the next admission. In this ten, only the wait between Arizona and Alaska is longer ^[1].

The official date is 4 January 1896. As with the other entries, earlier constitutional conventions and enabling acts are background, not a substitute for the effective admission day ^[1]^[2].

7. Wyoming

Wyoming was admitted on 10 July 1890, as the 44th state, one week after Idaho ^[1]^[3]. It was formed from Wyoming Territory. The week between the two July admissions is one of the shortest gaps in this list.

It is seventh as the later of those two 1890 states. Wyoming is also among the largest states by area and among the least populous, but those facts do not affect the admission rank ^[2].

The territorial boundaries and the later state boundaries are close to the familiar rectangle on today's map. The date that matters here is still 10 July 1890 ^[1]^[3]. Wyoming's admission is also often remembered for the territory's earlier voting laws, but that political history is a separate subject from the effective statehood date used in this ranking.

8. Idaho

Idaho was admitted on 3 July 1890, as the 43rd state, formed from Idaho Territory ^[1]^[3]. Together with Wyoming a week later, it closed a burst of northwestern admissions that had begun in November 1889.

It is eighth because Washington and Montana were admitted earlier, in 1889, even though all four states are often grouped in memory as a single late-nineteenth-century wave. The official calendar splits that wave across two years ^[1].

Idaho's admission date is sometimes overshadowed by the Independence Day holiday that follows it. The legal date remains 3 July ^[2]^[3].

9. Washington

Washington was admitted on 11 November 1889, as the 42nd state, formed from Washington Territory ^[1]^[3]. It was the last of four admissions in a ten-day stretch that also included the two Dakotas, just outside this ten, and Montana.

It is ninth as a later 1889 admission than Montana, and as the Pacific Northwest state that completed that November cluster. The date is the official effective date in the congressional compilation ^[1].

Washington Territory had been created in 1853. Statehood came 36 years later, which is a long territorial wait but a shorter one than Utah's or New Mexico's ^[3].

10. Montana

Montana was admitted on 8 November 1889, as the 41st state, formed from Montana Territory ^[1]^[3]. It is the earliest admission in this ten, six days after North Dakota and South Dakota, which were both admitted on 2 November 1889 and are the 39th and 40th states.

Those Dakota admissions are the reason Montana is tenth here rather than twelfth. A list of the last ten states starts after the Dakotas, with Montana on 8 November and Washington on 11 November ^[1]^[2].

The November 1889 cluster, sometimes called the admission of several northwestern states in a single month, is the opening of this modern ten. After Washington, the next state is Idaho the following July ^[1]^[3].

Conclusion

The official last ten admissions, from Montana on 8 November 1889 to Hawaii on 21 August 1959, are a closed historical list ^[1]^[2]. No state has been added since Hawaii, and the dates above are the effective dates used in congressional reference tables, not the dates of territorial organisation or of later anniversaries.

Two neighbouring facts help keep the calendar straight. The Dakotas, admitted on the same day in 1889, sit immediately before this ten. Alaska and Hawaii, both admitted in 1959, sit at the top of it, 47 years after Arizona completed the contiguous map ^[1]^[5]. For area rather than admission date, see Finepedia's ranking of the largest states. A later petition or a later anniversary does not change these dates, and a state can celebrate statehood on a local holiday without altering the federal effective day. That is why a 2026 list can still be short, dated, and complete: the last admission remains 21 August 1959, and the ten names above are the whole modern end of the calendar ^[1]^[4]. Anyone writing a school chart or a flag history can use the same ten dates without waiting for a new Census vintage, because admission, unlike population or economic rank, is a closed historical sequence until Congress and a future territory change it. Until that happens, Hawaii remains the last state, and 21 August 1959 remains the last admission date on the official list compiled for the present article.