The UIL has compiled 2017-18 enrollment data so it can determine which conference levels a high school's athletic teams will compete in for 2018 to 2020. The top conference level, 6A, consists of 253 schools with 2,190 or more students.
Allen High School in Allen, Texas, ranks as the most populous high school in 2017-18 with 6,664 students in grades nine to 12.
Here are the 10 Texas high schools that reported the largest enrollments in 2017-18.