The Alexanders came from Scotland and Ireland, and settled in Pennsylvania. Some of them moved to North Carolina, and Isaac or his father went to Georgia. An Isaac Alexander applied for land in Georgia at the end of the Revolutionary War, for service in the army. Isaac moved to Mercer County, Kentucky, where he raised his family. His will was probated in the Mercer County Court, September, 1838, Harrodsburg, Kentucky. In it he states that one son has already received his share of the estate, and that the estate was to be divided into eight shares, one for his wife, Chloe.

Isaac enlisted in Tyrrell County, North Carolina, in 1781, and served six months as a private in Captain Jones' Company, Colonel Javis' (Jarvis?) North Carolina Regiment. He was allowed a pension on his application executed May 6, 1833, at which time he was seventy years old and living in Mercer County, Kentucky. The widow Chloe was allowed a pension on her application executed February 17, 1844 at which time she was seventy-four years old and a resident of Boyle County, Kentucky.