[BeadCounter]

Make that just over 300 Mosques, still seems like a high number. Houses as Mosques maybe? Like some Chinese Buddhist Temples in the US operate out of houses.

[combat_boots]

http://hirr.hartsem.edu/mosque/database.html

[21twelve]

Lots of the “Mosques” around here are small store-front places in the run-down parts of town and small homes. Of course after awhile some of them grow and they can build an actual building that might look somewhat like a mosque.

[Charles Martel]

Make that just over 300 Mosques, still seems like a high number. Houses as Mosques maybe?

More likely unmarked locations in old, run-down strip shopping centers. Although I'm sure that a fair percentage are free-standing, purpose-built mosques (like the one that burned in Austin).