This holiday is always celebrated on 18 September and marks the date when the Chilean people declared independence from Spain.
Along with Christmas, this period is the most important holiday time in the year in Chile.
On 18 September 1810, Chile broke from Spanish rule, declaring their independence. The Spanish had ruled Chile since the middle of the Sixteenth Century. The movement to independence had been driven by other South American countries revolting against colonial rule, the French and Spanish warring in Europe and the appointment of an unpopular Governor in 1808.
While Chileans celebrate their independence on 18 September, their declaration in 1810 was the start of a long struggle and the Chilean war of Independence lasted for eight years before Chile could officially proclaim independence on 12 February 1818. Indeed, it wasn't until 1826 when the last Spanish troops holding out on a remote island finally surrendered to Chilean forces.
With Independence Day being immediately followed by another public holiday (see below), the whole week around those days tends to be a period of celebration. Many schools and some companies will declare a week long holiday.
The events around the struggle for Independence are remembered with the 'Fiestas Patrias' (national parties). These fiestas include parades (often including 'huasos', the traditional Chilean cowboys), dancing, partying, traditional Chilean food, and displays of national pride.
19 September, the day after Independence Day is also a national holiday in Chile. It is effectively the grand finale of the Independence celebrations.
It culminates in the Great Military Parade of Chile, led by the Chilean Armed Forces, which commemorates the glories of the Chilean Army, in Santiago's O'Higgins Park.