New Jersey Statutes Title 40A. Municipalities and Counties 40A § 6-1

a. First class--counties having a population of more than 550,000 and a population density of more than 3,000 persons per square mile;

b. Second class--all other counties having a population of more than 200,000 except such counties bordering on the Atlantic ocean;

c. Third class--counties having a population of not less than 50,000 but not more than 200,000 except such counties bordering on the Atlantic ocean;

d. Fourth class--counties having a population of less than 50,000 except such counties bordering on the Atlantic ocean;

e. Fifth class--counties bordering on the Atlantic ocean having a population of more than 125,000;

f. Sixth class--counties bordering on the Atlantic ocean having a population of not more than 125,000.