First found in Galway, where they held a family seat from very ancient times.

Irish Families began to immigrate to British North America and the United States in the 18th century, but the greatest influx of Irish immigrants came during the Great Potato Famine of the late 1840s. The earlier settlers came to North America after a great deal of consideration and by paying relatively high fees for their passage. These settlers were primarily drawn by the promise of land. Those later settlers that came during the 1840's were trying to escape the conditions of poverty, starvation, disease, and death that had stricken Ireland. Due to the enormity of their numbers and the late date of their arrival, these immigrants primarily became hired laborers instead of homesteading settlers like their predecessors. An exhaustive search of immigration and passenger lists has revealed many Irish immigrants North America bearing the name O'Fallon: Stephen Fallon lived in Pennsylvania in 1773; and many other Fallons later joined him there in the mid 1800's. The family also settled in New York, California, Massachusetts, during the 19th century. They also settled in Newfoundland between 1850 and 1871..

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