<P> Saint Patrick's Day, although a legal holiday only in Suffolk County, Massachusetts (where it is recognized alongside Evacuation Day) and Savannah, Georgia, is nonetheless widely recognized and celebrated throughout the United States . It is primarily celebrated as a recognition of Irish and Irish American culture; celebrations include prominent displays of the color green, eating and drinking, religious observances, and numerous parades . The holiday has been celebrated on the North American continent since the late 18th century . </P> <P> According to the National Retail Federation, consumers in the United States spent $4.4 billion on St. Patrick's Day in 2016 . This amount is down from the $4.8 billion spent in 2014 . </P>

When did the us start celebrating st patrick's day