* No central database tracks this information: Open campus policies are determined at the individual school or district level. There's no national or even state-wide organization consistently collecting this data.
* Definition varies: What constitutes an "open campus" can be quite fluid. Some schools might allow students to leave for lunch but not during class, while others might have more relaxed policies. The level of openness differs greatly.
To find out how many schools in a *specific area* have open campuses, you'd need to contact individual school districts or schools directly.