In 1856, a 23-Year-old widow became America’s first female detective. Years later, she helped save former US president Abraham Lincoln’s life

Long before fictional detectives such as Sherlock Holmes and Hercule Poirot captured readers' imaginations, a real-life investigator was breaking barriers in America. This woman slipped into different identities, gained suspects' confidence and gathered intelligence at a time when few people would have imagined a woman working as a professional detective. Her name was Kate Warne, and in 1856 she walked into Allan Pinkerton's Chicago detective agency looking for a job. What followed was a remarkable career that would take her from investigating major thefts to helping protect President-elect Abraham Lincoln.

A 23-year-old widow asked to become a detective

Warne was a 23-year-old widow when she approached Pinkerton. Allan Pinkerton initially assumed she was interested in clerical work because employing a woman as a detective was virtually unheard of. Warne had something else in mind. Warne argued that being a woman could actually make her a more effective investigator. She could enter social circles inaccessible to male detectives, befriend women connected to suspects and encourage people to reveal information without realising they were speaking to an investigator. Pinkerton took the chance. His company records list Warne's hiring in 1856 and describe her as its first female detective.

An embezzlement case proved her skills

One of Warne's early major assignments involved the Adams Express Company and its employee, Nathan Maroney, who was suspected of a large-scale theft. Warne went undercover and befriended Maroney's wife, gradually gaining her confidence. Pinkerton's historical account says Warne's work became part of a wider undercover operation that ultimately uncovered the hidden money. Nearly the entire amount was recovered, and Maroney was eventually sentenced to prison. Warne's success convinced Pinkerton of the value of female investigators. He subsequently created a female detective department and placed Warne in charge.

Then came Abraham Lincoln

Warne's most famous assignment arrived in early 1861. Abraham Lincoln had been elected president and was travelling towards Washington for his inauguration when Pinkerton agents investigating security threats surrounding the railroad uncovered an alleged plot to assassinate him in Baltimore. Warne infiltrated secessionist circles by posing as a Southern woman, reportedly using aliases including Mrs Cherry and Mrs Barley. She befriended women connected to suspected conspirators and helped gather information about the threat. The precise scale and seriousness of the so-called Baltimore Plot has remained a subject of historical debate. But Pinkerton believed the danger was real enough to secretly change Lincoln's journey.

Warne helped get Lincoln through Baltimore

On the crucial journey, Lincoln travelled overnight rather than making his scheduled public appearance in Baltimore. According to Smithsonian Magazine, Warne posed as the disguised president-elect's caregiver, presenting Lincoln as her "invalid brother". She helped secure privacy aboard the sleeping car as the group quietly passed through Baltimore. Lincoln reached Washington safely at around 6 a.m. on February 23, 1861. Warne's intelligence career continued after the Civil War began. She worked undercover gathering information about Confederate forces while Allan Pinkerton served as chief of intelligence for Union General George B. McClellan.

A remarkable career cut short

Warne did not live long enough to see how influential her career would become. She died of pneumonia in January 1868, aged only 34 or 35. Allan Pinkerton reportedly arranged for her burial in his family's plot at Chicago's Graceland Cemetery. Her career lasted barely 12 years, yet it challenged assumptions about what women could do professionally decades before American women gained the constitutional right to vote. Warne's greatest advantage was, ironically, the prejudice she encountered. In a society that rarely imagined a woman could be an investigator or intelligence operative, suspects often underestimated her. She turned that invisibility into a weapon and helped open a profession that had previously been closed to women.