As the green beer flows, everyone professes to be Irish in America on St. Patrick's day.

Originally a religious holiday to honor St. Patrick and the introduction of Christianity to Ireland, it has evolved to be a day to wear green, and celebrate anything and everything Irish.

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The U.S. Census has crunched the numbers to find out who is really Irish the 364 other days of the year.

>>Click here to see a large version of the census map

The findings:

  • 33.3 million people in the U.S. who claimed Irish heritage in 2013, seven times more than the entire population of Ireland.
  • 21.2 percent of the population of Massachusetts claim Irish ancestry, the highest in the country.
  • 22.1 percent of the Boston area claims Irish backgrounds, highest in the top 50 metro areas.
  • 16 towns in the U.S. that are named Dublin

There are also Emerald Isle, N.C., Irishtown, Ill., Clover, S.C., Clover, Ill. Clover, Pa. and six towns named Shamrock in the country to spend St. Patrick's Day.