The branch served the Union Stock Yards and the Canaryville neighborhood of Chicago and consisted of eight elevated stations.

The Stock Yards "L" branch opened on April 8, 1908; not only was it a popular line for workers, but also for tourists.

Conditions were extremely poor, and a 1934 fire in the Yard caused the shutdown of the line west of Halsted for six months while insurance disputes between the meat packers, the Junction Railroad and the Chicago Rapid Transit Company delayed repairs.

The Chicago Rapid Transit Company declared bankruptcy in 1947 and was taken over by the Chicago Transit Authority, which streamlined operations and cut unprofitable stations and routes out of the system; the rise of interstate trucking, refrigerated box cars, along with expensive property values in urban areas were slowly killing the Stock Yards; the line was extremely outdated (one of the last Elevated lines to use wooden cars from the early days of the "L") and sat on property and right of way loaned from the Junction Railroad, whose rental costs often exceeded revenue.

In 1956, another fire damaged Packers station; the loop was repaired a year later in April, however it was for naught as all service on the branch closed on October 6, 1957, due to extreme losses and declining ridership.