Peter was born in Menard Co. Illinois where his father died when he was four years old. He was living at home with his widowed mother on the 1850 census and farming with two brothers at age 26 on the 1860 census. He married at 31 and was living in Crane Creek Mason Co. Illinois with Nancy and his three oldest children on the 1870 census.
Peter is in Stohrville, Harper Co. Kansas on the 1880 census with only six of their then eight children. By 1890 the census shows them living in Township 11, Canadian, Oklahoma. It is here we have to take what information we have from stories. Floyd Harmon quoted in a book found in the Cheyenne Okla. Library said the Harmon's moved around a lot.
Peter and Nancy lived in Illinois for ten years after marriage in 1864. They then moved to Missouri around 1874 and at least two children may have been born there. However we think Newton was born in Kansas in 1875 as well as six of the other children they moved back and forth from Missouri to Kansas. The fact that Peter was moving freight may explain why
Peter made the run for land in the April 22,1889 at the site of present day El Reno Okla. and filed on land near Holdenville, Okla. Peter and Nancy had 15 children, their last child Harry was born May 21, 1889 in Chickasaw Indian Territory. Peter was a freight hauler and he drove a wagon between Oklahoma City and Santa Fe New Mexico. It was here crossing western Oklahoma he decided to purchase land and move the family. Peter died in 1911 and Nancy died in 1928. She lived with her son Harry after Peter's death.

Obituary
Peter Harmon, one of the old settlers of Roger Mills county, committed suicide last Sunday morning July 30, 1911 by hanging himself from a tree on his son's farm on Croton creek. No reason for the rash act is assigned other than that the deceased had been despondent for several weeks. Mr. Harmon was 80 years of age. He leaves a wife and three children, all of whom are now residents of Roger Mills county. The Sayre Standard, Sayre, OK 3-Aug-1911