Highest salary at Mchenry County in year 2017 was $204,482. Number of employees at Mchenry County in year 2017 was 1,212. Average annual salary was $51,592 and median salary was $44,579. Mchenry County average salary is 10 percent higher than USA average and median salary is 3 percent higher than USA median salary. From 2016 to 2017, the average salary of employees at this employer increased 2.1 percent, the median salary increased 0.4 percent.