Milward & Oldershaw
Milward and Oldershaw's Covington, Kentucky pork-packing plant was purportedly the largest facility in the nation when it was completed in 1851. It packed more than twenty-three thousand hogs during 1851-52 season. But, as Margaret Walsh has explained, the scale of these somewhat more substantial operations would pale in comparison to those of the larger Chicago packing operations just two decades later. In 1878-1879, both the Anglo-American Packing and Provision Company and Armour packed just under one million hogs in their Chicago plants.
from Wilson J. Warren's 2007 Tied to the Great Packing Machine: The Midwest and Meatpacking.