Charles Alexander Reynolds was the son of Joseph Boyer and Phoebe (Buah) Reynolds. Both the place and the date of his birth are in dispute. To a recruiting officer, in the summer of 1861, he stated that he was nineteen years old and that he was a native of Illinois, but it seems probable that he was born on a farm near Stephensburg, Hardin County, Kentucky. His paternal grandfather, Nathaniel Reynolds, of Scotch ancestry, brought his family from Virginia to Kentucky about 1811, served in the War of 1812, and was wounded at the battle of New Orleans. His father, born in Virginia, was reared in Kentucky, where he became a farmer and a practising physician. He later removed with his family to Illinois, and, early in 1859, to Atchison County, Kansas.