The story of Duncan-Miller glass began in 1865 when George Duncan bought the glass factory of Ripley & Company, a small building located at 10th and Carson Streets in Pittsburgh, Pennsylvania. He had been associated with D.C. Ripley and the company previously. Ultimately both men decided to seek other partners.

George Duncan formed the company of George Duncan & Sons, a partnership with his sons, Harry B. Duncan and James E. Duncan, and Augustus H. Heisey, the husband of his daughter, Susan. At that time the Southside of Pittsburgh was the industrial hub of the city. The factory was located just two blocks from the Monongahela River which provided an easy and cheap access, by barge, for the sand, silica and potash needed to make the glass, in addition to low cost coal for the furnaces.

One of the men who was persuaded to join the company in 1874 was John Ernest Miller, who had been in glass manufacturing for twenty years. He was foreman of the mould shop of King, Son and Company when Duncan hired him as a designer. His [George Duncan] decision was a wise one, for John Ernest Miller became internationally famous for his designs of Duncan and Miller glass during the next fifty-two years.

About 1890 The United States Glass Company succeeded in forming a glass trust by gaining control of the various Pittsburgh glass companies. Although George Duncan & Sons joined this combine, they were relieved to have the association end in 1892 when their plant was destroyed by fire. At this time Augustus Heisey decided to leave the company and start his own glass house in Newark, Ohio.

James E. Duncan Sr. had become head of the firm in 1877 when George Duncan died. He now selected a site for the new factory on Jefferson Avenue in Washington, Pennsylvania. Natural gas for the furnaces was plentiful and cheap in Washington County and the railroads replaced the barges in transporting the basic raw materials.

On January 3, 1893, the new plant was finished. The 16 Pot  Deep Eye furnace was fired up and th e first pattern to be made on February 9th was reputed to be the Mitchell pattern.

The period from 1893 to the closing of the plant in 1955 is generally known as the Duncan-Miller period, although the partnership structure was not changed until November 15, 1900, when the firm was incorporated as Duncan and Miller Glass Company. At that time John Ernest Miller became a stockholder along with members of the Duncan family.

The method of making hand made glass at the Duncan & Miller Glass Company was not much different than that of the numerous small plants scattered in the tri-state area of Pennsylvania, Ohio and West Virginia. Only the artistry of design, the skill of the workers, the batch formulas and the lovely colors have distinguished their glass from others of the time. Most pieces required that ten persons handle each piece. Some, like the famous swan, which is considered one of the finest pieces ever produced by any firm, required fourteen.

All the work...came to an abrupt end on June 13, 1955. Machines and assembly lines for making glassware made the production of fine hand made glass uneconomical and decision was made to close the plant. The inventory was advertised for sale and people came hundreds of miles to buy the last pieces of Duncan-Miller hand made glass at greatly reduced prices.

Most of the moulds, machinery and equipment were sold to the U.S. Glass Company to be used by their Duncan Division to make Duncan- ware.

The plant on Jefferson Avenue was finally sold but before the new owners, Andy Bros., could move in a fire completely destroyed the building on June 29, 1956.