Johnny, thanks for the response and information. Margaret Fitzgibbon, according to what I have, was born in Co. Clare, Ireland in 1834 and arrived in America in 1855. Her child by John Liddy, Dennis, was born in 1860 or 1861 in South Carolina, so I'd say she married Liddy between 1855 and 1859. After Liddy's death, she married Michael Moran, the U.S. Army soldier in January 1868 in Charleston. She is in the 1870 U.S. Census at Fort Sully, Dakota Territory. So the longest stretch of time she would have been in South Carolina would have been from 1855 to early 1870. The shortest would have been from 1860 to 1868.

Liddy is also a County Clare name in Ireland, so it is not impossible that Margaret Fitzgibbon and John Liddy came to America as husband and wife, although the gap of time, 1855 (her immigration) to 1859 (birth of her first child) seems long for a first child to be born to a couple, so I have assumed they married in America.