Andrew Ryan McGill, the son of Angeline (née Martin) and Charles McGill, was born in
Saegertown, Pennsylvania, on February 19, 1840. Andrew's father, Charles Dillon McGill (1802–1875), was the youngest son of Patrick (1762–1832) and Anna (née Baird) McGill. Patrick had emigrated from
County Antrim, Ireland, about 1774, settling in
Northumberland, Pennsylvania. In 1795 Patrick and Anna moved their family to the western part of Pennsylvania, homesteading several hundred acres in
Crawford County. Andrew's mother, Angeline Martin (1811–1849), was the eldest of Armand (1785–1861) and Mary (née Ryan, 1789–1866) Martin's nine children. The Martin family also owned land in western Pennsylvania. Armand's brother, Lieutenant General Charles Martin, who commanded troops stationed at Fort de Boueff (
Watertown, Pennsylvania) in the late 1790s, settled in
Carlisle, Pennsylvania. McGill married Eliza E. Bryant (d. 1877), daughter of Charles S. Bryant, a lawyer and author from
St. Peter, Minnesota. Together they had three children: Charles Herbert (b. 1866), Robert C. (b. 1869), and Lida B. (b. 1874). In 1879, two years after Eliza's death, Andrew married Mary E. Wilson, daughter of Margaret Maleena (née Stone) and Joseph Carlton Wilson, a prominent physician of
Edinboro, Pennsylvania. Mary and Andrew had two children: Wilson (b. 1884) and Thomas (b. 1889). ==Early career==