The 1873 financial crisis that helped trigger the Long Depression was the Panic of 1873.
The panic began in Europe and the United States after speculative investment in railways and property weakened. In the United States, the failure of Jay Cooke & Company in September 1873 damaged confidence because the firm had heavily promoted Northern Pacific Railway bonds. The New York Stock Exchange closed temporarily as financial stress spread.
The resulting downturn brought bank failures, business closures, unemployment, and falling prices across many economies. The period is called the Long Depression because economic weakness lasted for years, although its exact dates and severity varied by country.
It is distinct from the Great Depression that began in the 1930s. The 1873 crisis was also shaped by post-Civil War and post-Franco-Prussian War financial conditions, railway overbuilding, and changes in monetary systems. Historians debate the precise length of the depression, but the initial panic date is firmly associated with 1873.