Highest salary at Mchenry County in year 2019 was $210,366. Number of employees at Mchenry County in year 2019 was 1,211. Average annual salary was $52,677 and median salary was $47,857. Mchenry County average salary is 12 percent higher than USA average and median salary is 10 percent higher than USA median salary. From 2018 to 2019, the median salary increased 2.3 percent.