The tax on whiskey was bitterly and fiercely opposed on the frontier from the day it was passed. Western farmers considered it to be both unfair and discriminatory. As the Lower Mississippi River had been closed to American shipping for nearly a decade, farmers in western Pennsylvania were forced to turn their grain into whiskey. The substantial reduction in volume resulting from the distillation of grain into whiskey greatly reduced the cost to transport their crops to the populous east coast, which was the only place where there were markets for their crops. In mid-1794, the government began to crackdown on tax evasion, launching prosecutions against dozens of distilleries.