John Dean Caton (March 19, 1812, Monroe, New York – July 30, 1895) was an associate justice and chief justice of the Illinois Supreme Court.

Caton attended the Utica Academy in Utica, New York. After graduation, he worked as a teacher in Utica. During this period, Caton studied civil engineering and law. In 1833, Caton moved to Chicago, then a small town, and opened the first law office there with his partner, Giles Spring.

In his book, Early Bench and Bar of Illinois,^[1] inspired by an 1893 speech given to the Illinois Bar Association, Judge Caton claims to have tried the first jury case in a court of record in Cook County, Illinois. He recounts his experiences riding the circuit in the early days of Illinois statehood, and his later appointment to the Illinois Supreme Court, a period of some sixty years. He relates a number of humorous anecdotes about his days as a circuit rider.

Abraham Lincoln was an attorney in 214 cases in the Illinois Supreme Court in which Caton was a justice.^[2]

Judge Caton was an early adopter of telegraph technology when as a young lawyer he was asked by a Rochester, New York friend Henry O'Riley and his friends in Ottawa to organize the Illinois and Mississippi Telegraph Company at a meeting in Peoria, Illinois. Caton was elected one of the directors of the new company and played an active role in getting right of way for the erection of telegraph poles across the state. The Illinois and Mississippi Telegraph Company was a Morse patentee company was a profitable and well connected comapny on the western frontier after 1849. Caton and his Ottawa friends founded a telegraph instrument making company in Ottawa, Illinois, initially staffed largely by German immigrant instrument makers. Caton Telegraph Instrument Company was a large-scale producer of high-quality instruments and was a major supplier of instruments in the Illinois and Mississippi Valleys. Ottawa was the seat of the third district of the Illinois Supreme Court where Judge Caton presided. Caton and his interest in the Illinois and Mississippi Telegraph Company owned north-south telegraph lines that were a significant monopoly that was eventually key to the success of the Rochester based Western Union telegraph company's attempt to build line to St. Louis and further west as the Illinois and Mississippi and Caton's own private telegraph companies had agreements with most of the railroads in Illinois. Eventually, Caton and his friends sold the telegraph lines to Western Union and later, Caton sold his telegraph instrument manufacturing comapny located in Ottawa, Illinois to Western Electric Company which consolidated their Cleveland, Ohio manufacturing into the larger and more advance facility in Ottawa after the Civil War in 1868. The Ottawa telegraph instrument designs, patents, and production methods were eventually consolidated into the post-1872 Chicago Western Electric facilities on Kinzie Avenue. ^[3]