An "act of admission" by Congress is required to grant statehood.
The original acts that allowed new states were under the Articles of Confederation. The "Ordinance of 1784" and the "Northwest Ordinance" (1787) established the principle of forming new states rather than the expansion of existing ones. The Constitution adopted the principle that states could neither split nor merge (although this was subsequently allowed with West Virginia). The Enabling Act of 1802 allowed Ohio to form a state, and set the pattern for future statehood for parts of US territories.
All states must adopt the a form of government and a constitution in accordance to the US constitution before they are granted statehood. A territory will hold a referendum and if the majority votes for statehood, the Congress will be petitioned. If the Congress passes a joint resolution to grant statehood, the president signs it and statehood is granted to the territory.
First of all, Wyoming's population was smaller than the 60,000 that Congress generally used to grant statehood. Wyoming giving women the right to vote was also a concern to some Congressmen.
Puerto Ricans have been asked many times to vote on this. The people voted against Statehood (or left it blank, counted as a No vote). They remain US citizens in a Commonwealth.
The first states were:New Jersey (only property owners from 1790 to 1807)Wyoming (territorial law 1869)Utah territory (1870 to 1887, revoked by US Congress, restored 1895 before statehood)Colorado (1893)
Yellowstone signed into law by Ulysses S Grant in 1872
the statehood is April 28,1788
Judicial Review
Colorado sought Statehood once and the Legislation passed the US Congress only to be vetoed by the President. They had to wait until 1876 for the enabling legislation was approved and signed by President Grant.
Granting statehood
Delaware
It was the 7th US State.
By accepting the US Constitution.