Although glass was made here much earlier, West Virginia became an important glass manufacturing state at the end of the 19th century. The emergence of a significant glass sand industry in the Eastern Panhandle and the growing availability of cheap fuels, especially natural gas, provided the natural resources critical to glassmaking. At the same time, railroads had improved transportation in the state, and local booster movements in numerous towns aggressively recruited manufacturing enterprises to build on the plentiful natural resources. Finally, neighboring states, especially Pennsylvania and Ohio, were home to an abundance of skilled craftsmen still essential to glass production at a time when technological changes had just begun to restructure the industry.

By the mid-19th century, factories, firms, and workers were increasingly specialized in the various branches of glassmaking: glass tableware, bottles and containers, and flat glass (plate and window glass). Each of these branches gave rise to different processes, new technologies, distinct companies, and even separate labor organizations to represent the workers. The skilled craftsmen who made glass tableware joined the American Flint Glass Workers Union; bottlemakers were members of the Glass Bottle Blowers Association; and window-glass craftsmen created a powerful union organization in the Knights of Labor Local Assembly 300. Likewise, the factory owners and entrepreneurs in the industry tended to be small, select groups with particular knowledge of their industry niche.

Expanding markets and technological change dramatically altered all segments of the glass industry in the 1890s. One significant change involved the development of tanks for melting the raw materials for glass. Tank technology relied heavily on natural gas as the fuel of choice, dispersing the industry to western Pennsylvania, Indiana, and eventually, West Virginia. The tanks replaced the clay pots previously used, and allowed a higher production. Thus, companies built larger factories after the turn of the 20th century.

Complementing the tank, which affected each branch of glassmaking differently, were specific market factors and production technologies. In glass tableware, the industry expanded to meet the growing demand from the hotel and restaurant trade. This coincided with the development of presses and molds that reduced the skill required for producing high-quality tumblers, bowls, and goblets. New firms such as the Fostoria Glass Company and the Fenton Art Glass Company could move to where fuel was cheapest. Both began operation in Ohio but soon moved to West Virginia, to Moundsville and Williamstown, respectively, taking advantage of offers of cheap land and gas by local developers. Fenton and Fostoria both developed molds and presses that made the companies market leaders while enabling them to employ less skilled and less expensive workers. Early in the 20th century, Fostoria's more than 900 workers made it the largest glass tableware factory in the country.

Technological change brought window-glass manufacturing to West Virginia in a different fashion. Seeking to preserve more traditional production processes in the face of the monopolizing efforts of the American Window Glass Company, many skilled workers opened cooperatives or small, family owned plants in places such as Clarksburg, South Charleston, and Salem. Typically, immigrants, especially from France or Belgium, were at the center of these enterprises. In the first two decades of the 20th century, French was commonly spoken in neighborhoods around these plants. Ultimately, however, further advances in technology would eliminate the older process. By the late 1920s, window glass had become a mass-production industry with a few large firms dominating the market. Fortunately for workers in West Virginia, the Pittsburgh Plate Glass Company located one of its plants in Clarksburg in 1916, and the Libbey-Owens-Ford Company established a plant in Charleston in 1916, sustaining the industry in the Mountain State into the 1970s.

In glass bottles and containers, West Virginia was at the center of technological change due to the influence of Michael Owens, a native of Point Pleasant. Owens, working for the Libbey Glass Works in Toledo, patented and perfected his fully automatic bottle-blowing machine in the first years of the 20th century. In partnership with Edward Libbey, his former employer, Owens began his own company in 1909 to manufacture bottles, establishing his first plants in Fairmont and Clarksburg. Within 10 years Owens also had plants in Charleston and Huntington, making small-mouth, milk, soda, and whiskey bottles. Although the Clarksburg plant closed in the 1920s, the other three Owens plants employed thousands of employees for decades longer, Charleston closing in 1963, Fairmont in 1982, and Huntington in 1993. But unlike glass tableware and window glass, both of which brought large numbers of skilled workers to West Virginia, glass bottles began in the state with a mass-production process relying on less skilled factory labor.

In several segments of the glass industry, West Virginia companies led the nation. In pressed glass tableware, West Virginia was home to about 15 percent of the plants operating in the United States between 1825 and 1980, and between 15 per cent and 21 percent of the flat glass industry between 1947 and 1963. West Virginia accounted for an even larger share of the nation's production of glass bottles. Within the state, glass production ranked in the second tier of industries, far behind coal but close in importance to coke, chemicals, and steel in terms of number of employees and the value of its products. About 1910, glass factory employment totaled about 7,500 workers, making it the fourth-largest employer in the state.

In certain communities, glassmaking was far more important. Along the Ohio River, glass tableware was a significant employer in towns from Wellsburg to Williamstown; glass bottles and window glass plants shaped the landscapes of Clarksburg, Morgantown, Charleston, and South Charleston.

William John Blenko built his first factory in Milton in 1921 for the production of stained glass. In the 1930s, the company diversified and began to produce the decorative glassware that became its signature product. Blenko Glass has struggled financially, but it continues to operate at its facility in Milton.

In the early 20th century, the glass industry brought hundreds of migrants and immigrants to the state to fill the most skilled positions, while also recruiting thousands of native-born workers who entered the industrial world through glass manufacturing. By the 1930s, virtually all of these jobs were represented by unions, as the American Flint Glass Workers, the Glass Bottle Blowers Association, and the Federation of Flat Glass Workers adapted to meet the needs of mass-production workers.

Indeed, the glass industry produced important leaders for the state's labor movement; Rene Zabeau was a long-time officer in the West Virginia Federation of Labor from the 1940s to the 1960s, and Joseph Powell was president of the state AFL-CIO for more than two decades. Glassworkers also helped shape politics in their communities. After 1900, glass industry towns were noted for their tendency to vote for Socialist or Progressive candidates. Clarksburg, Salem, and South Charleston gave high percentages of their votes to Eugene Debs, and the small towns of Adamston, Harrison County, and Star City, Monongalia County, had Socialist mayors in the 1910s. In later years, many of these unionized glassworkers allied themselves with the liberal policies of the Democratic Party.