Saint Patrick’s Day is an annual feast day that celebrates Saint Patrick, the most commonly recognized of Irland’s patron saints, and is generally celebrated on 17th of March.
The day is a national holiday of Ireland: it is a bank holiday in Northern Ireland and a public holiday in the Republic of Ireland. In Canada, United Kingdom, Australia, the United States, Argentina and New Zealand, it is widely celebrated, but is not an official holiday.
Saint Patrick’s Day is celebrated worldwide by those of Irish descent and increasingly by people of other ethnicities as well, notably in Argentina, Australia, New Zealand and North America. Celebrations are generally themed around all things Irish and, by association, the color green. Both Christians and non-Christians celebrate the secular version of the holiday by wearing green, eating Irish food and/or green foods, imbibing Irish drink and attending parades, which have a particularly long history in the United States and in Canada. (from www.cute-calendar.com)