The first St. Patrick's Day on record in North America was in Boston, Massachusetts in 1737. I was unable to discover if the celebrants dyed their beer green in honor of the day.
St. Patrick's Day in Ireland
St. Patrick's Day in Ireland is much different; it's a public and religious holiday. Not saying a few beers mightn't get hoisted at O'Reilly's Pub, but in general it's a more cultural and sanctified event than its North American counterpart. People attend mass, watch parades and enjoy rugby games.
St. Patrick is not St. Patrick
Some historians believe his real name was Maewyn Succat. Even if it wasn't, it still wasn't Patrick but Patricius because he was born and raised in Roman Britain, probably on the coast of Wales.
When he was 16, Irish pirates raided the coast, taking him and many hapless more into Ireland where they were sold as slaves. Patricius remained a slave for six years, herding his master's sheep before escaping back home. He entered the church, eventually became a bishop and returned to Ireland as a missionary. He wasn't the first missionary there but does get most of the credit for establishing Christianity in Ireland.
One popular legend about St. Patrick is that he stood on a hill (Croagh Patrick to be exact) in County Mayo and with a wave of his staff, banished the snakes from Ireland. However, there never were any snakes in the Emerald Isle, making this a metaphor for something else. Serpents are often associated with paganism, especially goddess worship. Within 200 years of St. Patrick's arrival, Christianity dominated the country. Still, traces of the old goddess worship remain to this day. For example, the goddess Brighid became "Christianized" as St. Bridget. And there may be a good reason the Virgin Mary is so revered in Ireland that untold numbers of girls have been given the name.