The Chicago Board of Education voted in May to close the schools in an effort to reduce a $1 billion (£640 million) budget deficit.
Mayor Rahm Emanuel and schools chief Barbara Byrd-Bennett have claimed that the wholesale shut-downs will allow the district to improve academic provision.
But critics of the closures warned that minority students were disproportionately affected and that many students would now have to cross dangerous gang boundaries.
Some families have sued over the decision, but a federal judge refused to halt the plan.
Many students will now be guarded on their way to and from school by workers in yellow reflective vests, firefighters and even library security guards.
The guards will be stationed along designated routes across gang territories in what has been named safe passage.
"Safe passage is about more than just building a route to school," Mr Emanuel claimed last week.
"It is about building a route to college, career and beyond, so that once our kids get to school, they get the world-class education they deserve."
But safe passage is now the most visible sign of how much is at stake for students in a city that has long struggled academically and financially.