His gravestone spells his name as Simon P. Littleton, and gives his dates as 1823 - 1903. He was probably really born in 1821 or 1822, because his brother William S. Littleton was also reported as born about 1823, and was consistently younger in the censuses.

In 1900 he was recorded with his son James as Peter Littleton, 80, b. Nov 1820, widowed.

1850 census of Fleming Co., Ky, division 2, enumerated 27 Aug, lists on pp. 41-42 as family #279:
Peter Littleton, 29, farmer; Malinda, 29; Albert, 10; William F., 7; John R., 6; Margarett Ann, 4; Nancy E., 2; James A., 2/12. All born in Kentucky.

The next household is headed by Peter’s parents, Joseph Littleton age 57 and Elizabeth age 54. Following them is his brother, William S. Littleton age 27 with wife Margaret age 26. Four households above is a family headed by George Littleton age 42 with wife Mary age 37.

1860 census of Rowan Co., Ky, enumerated 31 July, lists on pp. 28-29 as family #211/215:
S. P. Littleton, 38, farmer; Malinda, 41; Albert, 20; William, 17; John R., 16; M. A. (f), 14; Nancy E., 12; James A., 10; Amandy R., 8; Francis H. (f), 6. All born in Kentucky.

The next household is headed by William Littleton age 37. The gender of Francis should be male, not female.

1870 census of Rowan Co., Ky, Pine Grove precinct, enumerated 22 June, lists on p. 1 as family #4:
Littleton, Peter, 48, farmer; Margaret, 22; James, 20; Amanda, 17; Frank, 15. All born in Kentucky.

The next household is headed by their son Albert.