Visitors will encounter locked doors with a buzzer. Parents will have to ring the bell and the office has to admit them into the building.
Superintendent Cindy Stevenson says voters in November made the extra layer of security possible.
Jeffco had already secured entries at 12 schools before the passage of 3A and 3B. Stevenson says there's no timetable yet for incorporating the system at the district's other 98 schools.