Highest salary at Nassau County in year 2019 was $272,005. Number of employees at Nassau County in year 2019 was 431. Average annual salary was $51,917 and median salary was $46,445. Nassau County average salary is 11 percent higher than USA average and median salary is 7 percent higher than USA median salary. From 2018 to 2019, the average salary of employees at this employer increased 7.8 percent, the median salary increased 4.1 percent.