McHenry County first earned its Aaa bond rating from Moody's Investors Service in 2010 and has maintained it through the most recent reevaluation in 2026. 

The Aaa bond rating is the highest possible rating that can be assigned to general obligation bonds and reflects McHenry County's strong economic base, robust financial position, and low long-term liabilities.  

Only 2 percent of counties have earned Aaa status nationwide.