He grew up in the rural part of the Town of Pomfret near the village of Fredonia, in Chautauqua County, New York.
William was one of at least eight siblings, five whom served their country in the United States Civil War, and four who passed away due to sickness or imprisonment during the war:
William born May 6, 1835 in Cambridgeshire, England.
James W. Apthorpe, born October 11, 1836 in Cambridgeshire, England, immigrated to the USA at the age of 10, grew up in Pomfret, New York, married Mary Barden, had a son named Lewis Henry Apthorpe, enlisted in the Union Army in August 1862, and passed away August 20, 1863 at the age of 26 years old due to sickness acquired while serving in the Union Army during the United States Civil War.
Henry Apthorpe, born June 23, 1838 and baptized about August 4, 1838 in Cambridgeshire, England, and passed away November 1, 1857 in Pomfret, New York.
George Apthorpe, born 1839 in England, immigrated to the USA in 1846 at the age of 7 years old, enlisted in the Union Army in August 1862, and passed away November 13, 1864 at Salisbury, North Carolina Confederate Prison Camp while serving in the Union Army during the United States Civil War.
Samuel Apthorpe, born 1841 in England, and passed away November 3, 1864 at Salisbury, North Carolina Confederate Prison Camp while serving in the Union Army during the United States Civil War.
Charles Apthorpe, Sr., born April 10, 1844 in England, who survived the United States Civil War, married his brother James W. Apthorpe]]'s widow Mary Barden, and had several children.
Mary Apthorpe, born about 1848 in Pomfret, Chautauqua County, New York, who married and had children.
Josiah Apthorpe, born in Pomfret, Chautaqua County, New York, who married and had children.
He enlisted in the United States Army, Company I of the 112th NY Infantry Regiment in August 30, 1862 to serve three years.
Pvt. William Apthorpe Jr. served in the United States Civil War. Enlisted: Aug 30, 1862 Mustered out: Nov 17, 1864 (DMS) Side: USA Regiment(s): 112th NY Infantry Regiment
William Apthorpe, Jr. passed away November 17, 1864 in Fredonia, New York, after being sent home on sick leave from sickness acquired while serving in the United States Civil War. Two of his brothers, Samuel and George, also passed away in November 1864 in a Confederate Prison Camp in Salisbury, North Carolina. HIs brother James W. Apthorpe had passed away in 1863, also while home on sick leave from sickness acquired while fighting in the US Civil War.
William Apthorpe, Jr. is buried in Pioneer Cemetery, Fredonia, Town of Pomfret, Chautauqua County, New York.
"England and Wales Census, 1841," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MQR6-93V : 12 December 2017), William Apthorpth in household of William Apthorpth, Caxton, Cambridgeshire, England; from "1841 England, Scotland and Wales census," database and images, findmypast (http://www.findmypast.com : n.d.); citing PRO HO 107, The National Archives, Kew, Surrey.