Irish-American population: 17.1% This city some 40 miles west of Boston has had a large Celtic population ever since Irish-born Tobias Boland brought in lots of his countrymen in the early 1800s to build the Blackstone Canal and the Boston and Worcester Railroad. Boland later went on to help found Worcester's College of the Holy Cross, a major U.S. Catholic institution to this day. Stephen Beldon of the Ancient Order of Hibernians' Worcester chapter says the 181,000-population city once had some distinct Irish neighborhoods, "but now everybody is spread out." The AOH runs a cultural center that hosts Celtic-themed dances, classes and a pub that features free Irish music every other Sunday. There are also several Irish Step Dancing academies in or around town, while the 3-year-old Worcester Hurling Club competes with other teams across New England. If you're interested in moving to Worcester, Zillow estimates the median home there costs $204,200 -- up 1.5% over the past year. There are some 1,300 homes listed on Zillow for sale in town.