I stumbled across these fascinating Sanborn Fire Insurance Maps of the three major packing houses in National City that surrounded the stockyards. Armour, above, still had a substantial portion of its plant still standing when I first saw it back in 2008, though of course it was gone by 2016.

Hunter, which was demolished in 2012, was much larger than what I originally saw it when it was already under demolition.

Swift was already completely demolished when I first visited the area, and the location as far as I could tell was completely covered in thick undergrowth and volunteer forest.