Col. J.B. Burton has the job of protecting 1 million people there.
His soldiers put down miles of concrete barriers along highways and community entrances to block carloads of al Qaeda thugs from attacking neighborhoods here called "mulhallas."
"Well they were just getting off the highway, and then exiting the highway back into these mulhallas, where they can prosecute their campaign of terror," Col. Burton said.
If good fences can make good neighbors, then in Baghdad, good walls can help make safer neighborhoods. Across West Baghdad, since these walls were put in place last November, the homicide rate has dropped from 275 a week to just ten a week.
It sounds like progress. Good news. Something everyone could agree on.
But not in Baghdad, which is more and more becoming walled off like a medieval city.
In an area called Adamiyah, a new wall will separate warring neighborhoods, one Sunni Muslim, the other Shia. The area is so dangerous that U.S. troops can build the wall only at night. The wall is 12 feet high, three miles long.
Not all residents are pleased with the addition.
"It never will keep us safe," says Quammer Al-Jabbi, an Adamiyah resident.
Al-Jabbi worries she'll be trapped in her Adamiyah neighborhood — with all the terrorists already dug in there.
"When I go inside my home, I never think that I will go out."
In West Baghdad, where the walls are lower, and people feel safer, most accept the disruption.
One resident says through a translator, "Thank you. Thank you for God."
"All of this stuff is meant to be temporary in nature, until the security situation is to a level that is acceptable to the people of Iraq," says Col. Burton.
But security is nowhere near acceptable. So walls here are everywhere and the city is more divided than ever.