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

Ireland saw an enormous decrease in its population in the 19th century due to immigration and death. This pattern of immigration began slowly in the late 18th century and gradually grew throughout the early portion of the 19th century. However, a dramatic increase in the country's immigration numbers occurred when the Great Potato Famine struck in the 1840s. The early immigrants to North America were primarily destined to be farmers tending to their own plot of land, those that came later initially settled within pre-established urban centers. These urban immigrants provided the cheap labor that the fast developing United States and soon to be Canada required. Regardless of their new lifestyle in North America, the Irish immigrants to the United States and Canada made invaluable contributions to their newly adopted societies. An investigation of immigrant and passenger lists revealed many Cahils: Elizabeth Cahill, a bonded passenger, who arrived in America in 1735; Thomas Cahill, an "enforced emigrant" sent to America from Ireland in 1737; Daniel Cahill, who arrived at Marblehead, MA in 1768.

Motto Translated: I trust in the Lord.

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