Vintage Pyrex Old Town Blue Onion milk glass mugs with diagonal handles.

Pyrex, a brand of heat-resistant and non-reactive borosilicate glass bakeware, was introduced by Corning Glass Works in 1915. It quickly became a staple in American kitchens due to its durability and versatility. Over the decades, Pyrex produced a wide array of dinnerware patterns, including the popular "Old Town Blue Onion" design, which was inspired by traditional European blue and white ceramics.

This particular "Old Town Blue Onion" pattern, often found on milk glass items like these mugs, was produced by Pyrex (Corning) during the mid-20th century. The diagonal handle design is a characteristic feature of some Pyrex mug lines from this era. These pieces are sought after by collectors for their retro aesthetic and nostalgic appeal, representing a significant part of American kitchen history.