I was under the impression that most of the Muslims of Dearborn had migrated to the "Promised Land" in Colorado. It was explicitly said that, majority of the population was migrants (with only a "warlord core" being made up of supermax escapees).Another Muslim region would be Dearborn, Michigan because it's got the second-highest Muslim population in the US, behind NYC of course. And I've always disliked how ugly the canon map of Islamic Colorado is. Why any medieval state would use straight lines for borders is beyond me.
And the only reason it had straight borders was because it was built on the county map, because it was used to give a rough impression of the Cowboy Range.