Drought conditions in some areas, along with weak grain prices, are among factors weighing heavily on the rural economy in parts of 10 Plains and Western states.
Wyoming's agriculture economy is part of the monthly calculation.
The overall Rural Mainstreet Index for the region plummeted to 40.7 in July from June's index of 50.
The index ranges between 0 and 100, with any number under 50 indicating a shrinking economy.
Creighton University economist Ernie Goss says July's was the largest one-month decline recorded in the index since November 2008, which was in the middle of the Great Recession.
The confidence index, which reflects bankers' expectations for the economy six months out, slumped to 38.4 this month from 48.9 in June.
Bankers from Colorado, Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota and Wyoming were surveyed.
Specifically in Wyoming, the July RMI to 40.0 from June's 48.1. The July farmland and ranchland-price index dipped to 36.1 from June's 38.7. Wyoming's new-hiring index improved slightly to 53.0 from 52.7 in June.
Much of Wyoming enjoyed a wetter than average winter and spring, but ag regions in the eastern part of the state did not. That area could experience drought conditions for a second straight summer.