John Cook was born in Belleville, Illinois, on June 12, 1825. His mother was related by marriage to Mrs. Abraham Lincoln; his father, Daniel P. Cook, was an early Illinois member of Congress for whom Cook County (Chicago) was named. Left an orphan at an early age, Cook was educated by his grandfather, Governor (and U. S. Senator) Ninian Edwards, and attended college in Jacksonville, Illinois. After learning the mercantile business in St. Louis, he entered into a partnership with his uncle in Springfield, Illinois, and later dealt in real estate. In 1855 he was elected mayor of Springfield; the following year, sheriff of Sangamon County; and then state quartermaster general. On April 25, 1861, Cook was commissioned colonel of the 7th Illinois Infantry, the first infantry regiment mustered into service in Illinois. For gallantry at the capture of Fort Donelson, where he commanded a brigade in C. F. Smith's division, Cook was promoted to brigadier general on March 21, 1862. After some Indian duty against the Sioux in the Department of the Northwest under General John Pope, Cook was assigned to the command of the District of Illinois, with headquarters at Springfield. He remained there until the end of the war. On August 24, 1865, he was brevetted major general of volunteers and mustered out the same day. In 1868, General Cook was elected to the lower house of the Illinois legislature from Sangamon County and in 1879 was awarded the Sioux agency in South Dakota known as the Rosebud. The later years of his life were spent in and near Ransom, Michigan, where he died on October 13, 1910. He was buried in Oak Ridge Cemetery, Springfield.
Medal of Honor Citation:
Volunteered at the age of 15 years to act as a cannoneer, and as such volunteer served a gun under a terrific fire of the enemy.
Reference: Generals in Blue. Lives of the Union Commanders by Ezra J. Warner. Louisiana State University Press. Baton Rouge.