One source, (SAR application) incorrectly gives his birth year as 1765. But his obituary, (Charleston Courier) as well as his tombstone give his age to be 67 years when he died in 1831, making his birth year 1764.
Colonel Lewis and wife, Sarah, had the following children:
Mary Mansfield Lewis (McDowell) 1790 - 1872;
James Overton Lewis 1792 - 1872;
Lindamira "Mira" Lewis 1795 - 1836;
Nancy "Ann" Elvira Lewis (Shanklin) 1799 - 1859;
Richard Marius Lewis, about 1799 - 1831 or 1843;
John Earle Lewis 1804 - 1839;
Eliza Love Lewis 1808 - 1893;
Sarah Ann Lewis (Reese) 1809 - 1865; and
Andrew Fielding Lewis 1814 - 1894

According to my family notes, Colonel Lewis purchased land in Pendleton, SC. Part of the land was purchased from Senator John C. Calhoun and the other section was purchased from the family of General Andrew Pickens for a total of 2,277 acres near the Seneca River. In 1820, he purchased 1,040 acres from Senator Calhoun and (not sure what date) he purchased 1,237 acres from Joseph Pickens, (part of the land grant awarded to General Pickens).

According to the Pendleton Historic Foundation, "Colonel Richard Lewis settled along the Seneca River after coming to the Pendleton area from North Carolina. Since the Lewis property must have been located between Pickens lands at Hopewell to the south and the Calhoun/Clemson property north of that, some of it could be under the waters of Lake Hartwell since so much of that property along the Seneca River was flooded."

There is also a copy of Colonel Lewis' will in the SC Wills & Probate Records, 1831, in Pickens Co, SC listing several people in his family.

Colonel Lewis and Sarah Miller married in 1790, according to SC Marriages & Southern Christian Advocate. I was not able to correct the marriage date on this page. Sarah was the daughter of Colonel James Miller and Agnes Miller, who were cousins, (from SAR application).