Mary Surratt's involvement in the American Civil War is primarily remembered for her alleged role in the conspiracy to assassinate President Abraham Lincoln. Born in 1820 in Maryland, Mary Surratt was the daughter of a plantation owner. She married John Surratt and moved to Washington, D.C., where they ran a boardinghouse known for its Confederate sympathies.

During the Civil War, Mary Surratt's boardinghouse became a gathering place for Confederate sympathizers, including John Wilkes Booth, who would later assassinate President Lincoln. While there is evidence suggesting that Mary Surratt was aware of Booth's plans, the extent of her involvement in the conspiracy remains a subject of historical debate.

On April 14, 1865, President Lincoln was assassinated by John Wilkes Booth at Ford's Theatre. In the ensuing days, authorities tracked down Booth and his co-conspirators, leading to a massive manhunt. Mary Surratt was arrested on April 17, 1865, along with several others suspected of involvement in the plot.

Surratt's trial was swift and controversial. Despite weak evidence linking her directly to the assassination plot, she was convicted by a military tribunal and sentenced to death. On July 7, 1865, Mary Surratt became the first woman to be executed by the United States federal government when she was hanged alongside three other co-conspirators.

The case of Mary Surratt remains a point of contention among historians. While some believe she was a willing participant in the conspiracy to assassinate President Lincoln, others argue that she was unfairly convicted based on circumstantial evidence and her association with Confederate sympathizers.

Regardless of her actual involvement in the assassination plot, Mary Surratt's story serves as a reminder of the complexities and moral ambiguities of the Civil War era. Her trial and execution sparked debate over issues of due process, military justice, and the limits of executive authority during times of war.