The average accountant salary at Ontario was $107,499 , which is 4 percent lower than the average salary for this job in California, and 4 percent lower than the national average for this job . Accountant salaries at Ontario typically range from $97,256 to $117,741 (25th to 75th percentile). The highest reported accountant salary was $125,432. There are 4 employees at Ontario with the job title accountant.