From Ohio History Central
During the first five decades of the twentieth century, the United States of America became involved in two world wars. World War I lasted from 1914 until 1919, while World War II raged from 1939 to 1945. The United States did not formally become involved in World War I until 1917 and in World War II until 1941. Although delayed, American involvement in both conflicts helped turn the tide of victory to the allies of the United States.
[[:Category:View the World Wars entries.