Never heard of this company, but a quick search tells me:
The company was established as a partnership in 1875 in Girard, Pa., but did not incorporate under the name Girard Wrench Mfg. Co. until 1902. The company continued in business until the 1920s.
They have some interesting patents, too. After I clean up the rust and work on the handle wood a bit, this is going to be a really nice wrench. It works perfectly.
