The Forgotten Depression of 1920-1921 was a sharp economic downturn that followed World War I. Unlike the long and severe Great Depression of the 1930s, this crisis was characterized by a rapid decline in industrial production, a significant drop in prices, and a sharp increase in unemployment, all occurring within a short period of time. The United States experienced deflation, which further exacerbated the economic troubles. Factors contributing to the crisis included the return to a peacetime economy, adjustments in supply chains, and the tightening of monetary policy by the Federal Reserve, which aimed to combat post-war inflation. Despite its severity, the depression was relatively brief, lasting approximately 18 months, as the economy recovered quickly starting in mid-1921.
Source: McElvaine, Robert S. "The Great Depression: America, 1929-1941." (1993).