Teacher duty day starts at 7:25a, with late bell/class start at 7:45a. Students are definitely let in by then. Earlier than that probably varies by school for when they unlock the doors generally. My HS used to by open around 7:00a, but halls unsupervised. Then when we had some student issues in winter, building security was tightened up and the doors were not unlocked until around 7:15a when security was available to monitor the doors and check student IDs.

I’ve dropped my kids off at their MCPS HS as early as 7:15 because they needed to meet a teacher. It was not an issue for them to go inside. I’m not sure what the official policy is though.

In AACPS (Anne Arundel), there is a designated time when student supervision starts every day (usually 8:10 AM; school starts at 8:30). If students' buses or parents drop them off at school prior to that time, they must wait in front of the main entrance or at the bus drop off area until the first bell rings at 8:10. Curious about how this works in MCPS.