California Admission Day is a legal holiday in the state of California in the United States. It commemorates the admission of California as the thirty-first state to the Union on September 9, 1850.

History:

After the Mexican-American War ended with the Treaty of Guadalupe Hidalgo in 1848, California was ceded to the United States by Mexico. The discovery of gold at Sutter's Mill in 1848 led to a rapid influx of people (the "Forty-Niners") during the California Gold Rush, accelerating its path to statehood.

Traditions:

While it used to be celebrated widely across the state with parades, historical reenactments, and educational events, California Admission Day has become a more low-key affair over time. Some local communities may hold small events or discussions on state history.

Modern Observance:

Today, it is largely an observance by local governments and history enthusiasts rather than a large state-wide celebration. Government offices and some schools may close, but for many Californians, it is a regular working day. Those who do observe it might visit historical sites related to statehood or participate in discussions about Californian history.