Highest salary at Mchenry County in year 2018 was $200,077. Number of employees at Mchenry County in year 2018 was 1,213. Average annual salary was $52,791 and median salary was $46,785. Mchenry County average salary is 13 percent higher than USA average and median salary is 8 percent higher than USA median salary. From 2017 to 2018, the average salary of employees at this employer increased 2.3 percent, the median salary increased 5.0 percent.