Cal. Ed. Code § 1205
For the purposes of prescribing the qualifications required of county superintendents of schools the counties are classified on the basis of the average daily attendance in the public schools as follows:
Class one (1) includes all counties with an average daily attendance of seven hundred fifty thousand (750,000) and over.
Class two (2) includes all counties with an average daily attendance of one hundred forty thousand (140,000) to seven hundred forty-nine thousand nine hundred ninety-nine (749,999), inclusive.
Class three (3) includes all counties with an average daily attendance of sixty thousand (60,000) to one hundred thirty-nine thousand nine hundred ninety-nine (139,999), inclusive.
Class four (4) includes all counties with an average daily attendance of thirty thousand (30,000) to fifty-nine thousand nine hundred ninety-nine (59,999), inclusive.
Class five (5) includes all counties with an average daily attendance of fifteen thousand (15,000) to twenty-nine thousand nine hundred ninety-nine (29,999), inclusive.
Class six (6) includes all counties with an average daily attendance of seven thousand (7,000) to fourteen thousand nine hundred ninety-nine (14,999), inclusive.
Class seven (7) includes all counties with an average daily attendance of one thousand (1,000) to six thousand nine hundred ninety-nine (6,999), inclusive.
Class eight (8) includes all counties with an average daily attendance of under one thousand (1,000).
Ca. Educ. Code § 1205