The several school districts of the Commonwealth are hereby divided into five classes, as follows:
Each school district having a population of one million (1,000,000), or more, shall be a school district of the first class;
Each school district having a population of two hundred fifty thousand (250,000), or more, but of less than one million (1,000,000), shall be a school district of the first class A;
Each school district having a population of thirty thousand (30,000), or more, but of less than two hundred fifty thousand (250,000), shall be a school district of the second class;
Each school district having a population of five thousand (5,000), or more, but of less than thirty thousand (30,000), shall be a school district of the third class.
Each school district having a population of less than five thousand (5,000) shall be a school district of the fourth class.
24 P.S. § 2-202