William was born in 1803 in New York to John P. Pournelle and Scarborough Merrill. His parents made frequent long term stays in the Long Island area on business, but eventually stayed put in Savannah, Chatham County, Georgia, building up their business there; Savannah is on the coast at the South Carolina border. William was somehow connected to the Union School Society in Savannah and my best guess is as an instructor of some type; the school was mentioned as part of a biographical sketch about William. The school's mission, as stated in 1821, was to provide an education and home for orphan boys. Today it is the Bethesda Union Society, a private military academy for boys. About 1823 William married Martha Ann Fairchild, who was born in 1807 in South Carolina and was about age 16. Their first child was born about 1825, but that daughter died at age 12. They had 8 more children, who all lived into adulthood, but several did die before the age of 40. The Pournelle family were members of the M. E. Church (Methodist).
Martha Fairchild's maiden name could have also been Barwick, as she is listed as M. B. Pournelle in her obituary, the cemetery index and on her grave marker, where the B could have stood for Barwick. Martha could also possibly be the daughter of Aaron Fairchild, who moved to Washington County, Virginia and then to Charleston, South Carolina, where he married a woman named Ann. Aaron died in Charleston in October 1809 and perhaps Ann remarried to Mr. Barwick, making Martha, then age 2, his step daughter. Martha's obituary states she had a half brother named W. B. Barwick.
William is found on the 1830 and 1840 census records for Washington County, Georgia in what was later the city of Sandersville with his family; Washington County is in the middle of Georgia. He served as sheriff of the this county for some years according to his wife's obituary. These early 1830 and 1840 census records do not record much info and only the head of household is named. However, I did find William also listed on the 1830 and 1840 Slave Schedules Censuses. In 1830 he had 2 slaves, one male between age 36-54 and 1 female between age of 10-12. In 1840, he had 5 slaves, one male between 10-23, one male between 36-54, two females between 10-23 and one female between 36-54. He is listed with his family on the 1850 census still in Washington County and he had 2 slaves, two females ages 20 and 1. These were probably household staff, some with children. A biographical sketch about William also states he was a partner with Joseph E. Kelly in a cabinet making and furniture repair shop, but the partnership was dissolved on 13 July 1852 and William continued the business on his own. At some point after 1852 and before 1860, a fire destroyed the shop and William and Martha moved to Savannah with their family. In 1860, they have moved a short distance to Egypt, Effingham County, Georgia, which was just north of Savannah; William is listed as a proprietor of a hotel and has real estate worth $1200 and a personal worth of $5155. By 1870 they have moved again and are now in Augusta, Richmond County, Georgia, living with their son, John Benjamin Pournelle and his wife; William has no occupation listed. Augusta is about half way up the South Carolina border from the coast. I could not find them in 1880, but William died on 17 August 1885 in Augusta of angina pectoris (coronary artery disease) at age 82 and was buried in Magnolia Cemetery in Augusta. His wife, Martha, lived 11 more years and died 14 December 1896 in Augusta, of exhaustion and senility at age 89. She was buried next to her husband in Magnolia Cemetery.