Hartshorn (pronounced HARTS-hurn, though New Englanders in this region usually pronounce it "HAHTZ-hun") was born on July 14, 1840 to Susannah Putnam Hartshorn (1816–1903) and her husband, John Hartshorn (1811–1878), a deacon in the Baptist Church. The younger Hartshorn grew up in South Lyndeborough in a house at the corner of what today is Citizens' Hall Road and &lt;a href="New%20Hampshire%20Route%2031"&gt;Forest Road/Route 31&lt;/a&gt;. On May 20, 1861, he enlisted in the 2nd New Hampshire Volunteer Regiment, infantry division, and served as part of the Army of the Potomac in Virginia. On May 5, 1862, Hartshorn was killed during the Battle of Williamsburg in Virginia, becoming the second Lyndeborough resident to die in the Civil War. Harvey Holt, the namesake for the GAR post, was the town's—and according to Lyndeborough's official town history, state's—first Civil War fatality, having perished during the First Battle of Bull Run.