The 1873 financial crisis that helped begin the Long Depression was the Panic of 1873.
The panic started in Vienna in May 1873 and spread to other financial centers, including New York. In the United States, the failure of the investment bank Jay Cooke & Company in September helped trigger a major market collapse and a suspension of trading on the New York Stock Exchange.
Railway speculation was an important vulnerability. Rail companies had expanded rapidly with borrowed money, and declining returns made debts harder to service. The crisis also reflected international financial pressures and a broader decline in investment.
The Long Depression lasted for many years, although its timing and severity differed between countries. It was not the same event as the Great Depression of the 1930s. The 1873 panic is also sometimes called the Great Depression of the nineteenth century, which can cause confusion with the later crisis.