* Largest student enrollment: This is likely the most common interpretation. Unfortunately, publicly available data that definitively ranks all Georgia high schools by enrollment fluctuates and isn't consistently compiled in a single, readily accessible source.
* Largest physical size (campus): This would require comparing the land area of each high school, data which is not readily available publicly.
Therefore, I cannot give you a definitive answer to which high school is the biggest in Georgia without access to a constantly updated, comprehensive database of all Georgia high schools and their enrollment or campus size.