Judge John Jay Jackson Jr. (August 4, 1824 - September 2, 1907) was born near Parkersburg. A year after his graduation from the College of New Jersey (now Princeton University) in 1845, he was admitted to the bar and joined his prominent father in the practice of law.

Jackson served as a prosecuting attorney of Wirt County (1848) and Ritchie County (1849) and as a Whig member of the General Assembly of Virginia (1851-55). In the political maneuvering over secession in the spring of 1861, he took a strong stand for the Union. In August 1861, Abraham Lincoln appointed Jackson a federal district judge, and his court became a symbol and agency of federal power in northwestern Virginia and later West Virginia. Some Republicans criticized him for his narrow interpretation of laws aimed at Southern sympathizers, thinking him too lenient, but he retained the confidence of President Lincoln. In 1870, Jackson's appointment of federal commissioners to supervise elections in West Virginia opened the vote to ex-Confederates and led to Democratic control of the state.

In later years, Jackson became notorious among those trying to organize labor unions in West Virginia. In August 1897, he issued an injunction against Eugene V. Debs and others that effectively ended a union campaign to organize West Virginia miners. Five years later, he blocked an effort by Mother Jones and other United Mine Workers leaders to organize the miners of northern West Virginia.

Jackson was a commanding figure both on the bench and off and, after age 80, continued his daily horseback rides across town to his court in Parkersburg. At the time of his retirement in 1905, he had served 44 years, longer than any other federal judge. Judge Jackson died in Atlantic City.