I am researching my GGGrandfather, William Hannan, whom I have just learned, through looking at a baptismal record of one of his children, came from County Sligo.
I have not been able to pin down his birth date yet, as he gave the age "40" on every census after 1850. However, using the information he provided in 1850, I estimate his birth year to be about 1822. His middle name MAY have been Charles, and he MAY have had a brother named John or James.
William immigrated to New York City in 1845, where he married Eliza McMullen and had several children, including a James, Sarah, and my GGrandmother Mary. His occupation in 1850 was "publican", but later it was listed as "grocer".
When Eliza died circa 1863, he married Annie Nichols from Scotland. About 1865 they moved to Jersey City, New Jersey. William and Annie had five children, and the three who survived childhood were named William, John, and Ellen (or Nellie).
If anyone in Sligo, Ireland is missing a William who immigrated to America in 1845 in their family tree, I'd love to hear from them!