Samuel Estill was born in Menard County, Illinois, on October 24, 1824, to William Estill and Mary Williams. His father was a farmer who owned $2,160 of personal property in 1860. Estill grew up in Menard County, and by 1850, he was working as a carpenter. He married Martha Jenison there on April 14, 1855, and their son Joseph was born around 1857. By 1860, they owned $1,825 of real estate and $625 of personal property.
On September 18, 1862, Estill received a commission as a captain in Company K of the 114th Illinois Infantry. The regiment took part in the siege of Vicksburg. Estill reportedly “received a sunstroke while in the service,” and he resigned on August 6, 1863, and returned home to Menard County. His son Joseph died around 1865, and his wife died soon afterward, on November 1, 1866.
By 1870, Estill was working as a lumber merchant, and he owned $7,000 of real estate and $4,000 of personal property. He married Rosa Mills on May 29, 1872, and they had at least four children: Blanche, born around 1876; Frank, born around 1879; Jette, born around 1883; and Fay, born around 1885. He applied for a federal pension in February 1886, having “been in poor health ever since he came home from the war.” His health deteriorated even further around 1899, and he died in Menard County on May 1, 1900.