By the early 20th century, West Virginia ranked first in the production of bituminous coal and high in the output of crude oil and natural gas. World War I accelerated industrial development, particularly in steel and chemicals. In the 1920's, the state was the scene of armed violence, especially iri Mingo and Logan counties, during the struggle for unionization of the coal industry by the United Mine Workers.

Economic growth was halted by the Great Depression of the 1930's, and West Virginia suffered acutely. In 1932 voters turned out of office the Republican party, which had controlled government since the turn of the century, and elected Democrats who supported the New Deal programs of the Roosevelt administration. Prosperity revived temporarily as a result of the production demands of World War II.

In the 1950's and 1960's, population declined as coal mines were shut down, the result of the increasing popularity of other fuels, and as machinery replaced workers. Some 250,000 people left the state during 1950–70. The plight of West Virginia and other states of Appalachia was an issue during the 1960 Presidential campaign and led to numerous federal programs that brought some aid to the chronically depressed region. In the 1960's, tourism began to be an important revenue source.

There was a brief upsurge in demand for coal during the international oil crisis of the 1970's. However, during the late 1970's and early 1980's, coal mining, still the state's main industry, was severely affected by slumping production following prolonged strikes and decreased demand. The depressed condition of the steel industry nationwide added to the state's economic problems and resulted in record unemployment in the mid-1980's. Economic recovery did not begin until the 1990's.

In the 1990s, coal production, the timber industry, and tourism expanded to help the economic situation. From 1990 to 2000, the state’s population increased by about one percent, and Robert C. Byrd, chairman of the U.S. Senate Appropriations Committee and from the state, helped West Virginia gain federal projects that created more jobs. These included an FBI fingerprint center at Clarksburg as well as federal highway construction and water development projects. In January, 2006, 14 miners died in two separate incidents. Subsequently, the West Virginia State Legislature passed new mine safety laws, calling for better lost miner tracking systems, stockpiled oxygen for them, and improved emergency response times.