First found in County Clare, where they were seated from very ancient times. They were descended from O'Dea who in turn was descended from the Heremon Kings.

The 19th century saw a great wave of Irish migrating out of their homeland in a great measure due to the oppressive imperial policies of the English government and landowners. Many of these Irish Families sailed to North America aboard overcrowded passenger ships. By far, the largest influx of Irish immigrants to North America occured with Great Potato Famine during the late 1840s. These particular immigrants were instrumental in creation of the United States and Canada as major industrial nations because the many essential elements such as the roadways, canals, bridges, and railways required an enormous quantity of cheap labor, which these poor immigrants provided. Later generations of Irish in these countries also went on to make valuable contributions in such fields as the arts, commerce, politics, and education. Extensive research into immigration and passenger lists has revealed many early immigrants bearing the name Day: Stephen Day who became a prominent merchant in Virginia soon after arriving in 1638. Another Stephen Daye (1594-1668), was the first printer in New England, and produced the first book printed in the English colonies. Cambridge Massachusetts granted his three hundred acres of land for "being the first that sett upon printing." A large contingent of the family also settled in Canada beginning in the 1840's..

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