How Many High Schools Are Located in Texas? We'll get to the biggest public high school in Texas soon, but before that, I think you should know how many high schools are in the state. Data from Public School Review shows that the biggest public high school is in Allen Texas -- named Allen High School. Allen High School also happens to have one of the most expensive high school football stadiums in Texas, with a reported construction cost of $70 million. The 10 Largest High Schools in TexasKeep scrolling to find out the top 10 biggest high schools in Texas, in ascending order:Here are the 10 Biggest Public High Schools in Texas Texas has MANY schools and districts.