Oklahoma was the only state admitted into the union during 1907. Oklahoma was admitted into the Union on November 16, 1907 becoming the 46th state to join the Union.
There is no limit to the number of states that may be admitted to the Union.
In 1866, there were 37 states in the United States. This was after the Civil War and during the Reconstruction era, as several Southern states had been re-admitted to the Union after their secession. The last state to join before 1866 was West Virginia, which became a state in 1863.
Eleven
11 States
All New England states remained in the Union during the Civil war.
During the civil war there were 24 states in the union including the border states. but there was 23 states that remained loyal to the union during the war.
During Andrew Johnson's Presidency, the 37th state, Nebraska, was admitted to the union, on March 1, 1867.
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35
There were 430,929 slaves in the Border States.