In the 1850 Census, taken in Moon Township., Allegheny Co., PA: Robert Harper, born in PA, was 28. His wife, Mary (nee Gleasen), also born in PA, was 29. their children were John Harper 7, born PA; Charles Harper, 5, born PA; Margaret Harper, 3, born PA; Robert Harper, 1 month, born PA. Robert was a ship carpenter. His real estate was valued at $200. He was most likely living in, or near, Shousetown which lay in the portion of Moon Township that was split off to form Crescent Township in 1855. There was a large shipbuilding business in Shousetown that dated back to the early 1800s.

Not listed in the 1850 Census was David Harper, born ca 1848. If Robert and Mary were living in what is now Crescent Township, David was most likely buried in the Shousetown Cemetery. That cemetery, on the banks of the Ohio River, was eroding away and the graves that remained were moved to the cemetery's current location

The family moved to Ohio sometime between the births of his children Alonzo (born PA, 1853) and Mary (born OH, 1857), and he took up farming. Robert was not found in the 1860 Census.

In 1870 the family was living in Liberty Twp., Jackson Co., OH: Robert was 51. His wife, Mary, died in 1861 and he had married Marinda, nee Byron, 35, who was born in OH. Living with them were his sons, Robert, 20, Alonzo Harper, 18, from his first marriage and Purley, 10, Arizona, 8, Orland, 5, and Leander, 3 from his second marriage. All the children were born in Ohio. Robert had done well for himself, as his real estate was valued at $2,500 and his personal property at $600.

In 1880 Robert and Marinda were living in Liberty Twp., Jackson Co., OH. With them were Marion A., 17, Orland B., 15, Joseph, 14, born OH, Leander, 12, Emma V., 7, Rosa, 6, and Eliza, 3. All the children were born in Ohio. Robert was still listed as a farmer.

Robert died on 12 Mar 1900, before the 1900 census was taken.