Hawaii became part of the United States on August 12, 1898, when it was annexed by the U.S. under the Newlands Resolution. Later, Hawaii was organized as a U.S. territory on April 30, 1900. Eventually, Hawaii was admitted as the 50th U.S. state on August 21, 1959, officially joining the Union as a state.

Key Dates:

• August 12, 1898: Annexation of Hawaii by the United States (became a U.S. territory)
• April 30, 1900: Hawaii officially organized as a U.S. Territory
• August 21, 1959: Hawaii admitted as the 50th U.S. State

The annexation followed the overthrow of the Kingdom of Hawaii in 1893, leading to its status as an independent republic until annexation. Statehood was achieved after a referendum and political process culminating in 1959.