The states that were admitted in the 20th century was Oklahoma, New mexico, Arizona, Alaska, and Hawaii. I looked up this information because i was also asking the same thing. I hope this helps you as much as it helped me.
It was the 20th state to join the Union.
It joined the Union as the 20th US State on 10 December 1817. It seceded from the Union on 9 January 1861 and was readmitted on 23 February 1870.
Puerto Rico
The final borders of the lower 48 states were established in 1959, when Alaska and Hawaii were admitted to the Union. Prior to that, the borders of the contiguous United States were largely set by the mid-20th century through a combination of treaties, purchases, and state admissions. The last significant adjustments to state borders occurred in the early 1900s, but the overall configuration was largely stable by the time Alaska and Hawaii joined.
The Soviet Union no longer exists. Back in the 20th century, when there still was a Soviet Union, its greatest width was approximately 7,500 miles across.
Oklahoma (1907), New Mexico (1912), Arizona (1912), Alaska (1959), and Hawaii (1959) were admitted to the union during the 20th century.
States admitted in the 20th century: Oklahoma, New Mexico, Arizona, Alaska, and Hawaii.
The Soviet Union.
Arizona was admitted into the union during the 20th century. Arizona was admitted into the Union on February 14, 1912 becoming the 48th state to join the Union. California was admitted into the Union on September 9, 1850 becoming the 31st state to join the Union. Vermont was admitted into the Union on March 4, 1791 becoming the 14th state to join the union.
Mississippi became the 20th state admitted to the Union on December 10, 1817.
Oklahoma was granted statehood on November 16, 1907. It was the first of five new states added during the 20th century.
Mississippi joined the Union on December 10, 1817 - as the 20th State
It was Joseph Stalin.
The Cold War.
Mississippi was #20 and Alaska #49,
It was the 20th state to join the Union.
The United States of America