C-Mon was named after it's founder Carl Edward
Monkhouse Sr. and was based out of Ellicottville, New York.
The company also made (or more likely relabeled) brushes in Germany. When the company was located in Germany (1920's & 1930's) their exclusive United States distributor was Peter J. Michels.
Mr. Monkhouse came to the United States in 1937 and settled in San Francisco doing business as the Ace Cutlery Company. The company was later moved to Allegany, New York and was eventually operated by his son, Carl Monkhouse, Jr. and then by his grandson, Carl Monkhouse III. The Monkhouse family still runs a company Carl Sr. founded in 1937 called Cutlery Associates.
Vintage straight razors, scissors and shaving brushes by C-Mon are still well sought after items today.
Note: Some C-Mon brushes have a diamond-e symbol and others have a circle-s symbol
C-Mon Price List - 1953
C-Mon Catalog 41 
C-Mon Catalog 50 
77-Series Brushes [From 1954 & 1963 C-Mon Catalogs]
Disclaimer: This site is not affiliated or endorsed by Rubberset Company, a division of the Sherwin-Williams Company. Rubberset Company has a website with their summarized history here. This site is exclusively concerned with the early history of the company as it relates to their shaving brushes and was compiled from public information freely available on the web. It is intended to be informational in nature, not commercial.