Hi Gary, According to the Standard Reference, the Square G was made 1940's - 1950's by the Glenshaw Glass Co., Glenshaw PA. This jar isn't really all that easy to find, but there currently isn't a lot of excitement generated over clear WWII era mason jars, which is reflected in the very reasonable pricing. Maybe if you hang on to it for another 20 years or so...... -Tammy