Violence in Baghdad and Iraq’s other cities can be spatially described in several ways. Newspapers usually report acts of violence as occurring in a particular neighborhood or along a named street. The U.S. military and Iraqi security forces analyze acts of violence in particular units’ areas of responsibility. Militias and insurgent groups might divide the city into zones. Elected Iraqi authorities probably think about violence in a particular electoral district, municipal council area, or in ethnic enclaves. In this paper, I assess the extent to which violence is better described through religious geography. I argue that Friday mosque sermons disseminate common knowledge within a geographically-bounded space, allowing individuals to know what others know in that mosque’s catchment area. This common knowledge helps neighbors coordinate and provide local social orders. Distinct social orders should emerge around mosques. From this, I hypothesize that murders and other violent crimes should be more common in areas far from mosques or in overlapping catchment areas than in areas wholly within a single mosque’s catchment area. The frequency of insurgent-based violence, however, should vary by the type of mosque. To tests these and other related conjectures, I constructed a geographic information system (GIS) that includes data on over 400 mosques in Baghdad, over 391,000 violent events (e.g. murders, assassinations, kidnappings, insurgent attacks, and counterinsurgent operations) that occurred in Iraq from January 2004 to December 2009, and geographic and demographic data on Baghdad. I use GIS techniques to analyze spatial relationships between frequency and type of attacks and mosques’ location and preachers’ political affiliation. I also use temporal data and case studies of mosques to assess the impact of Sunni Arab and Sadrist participation in the political process on insurgent violence. In particular, I try to assess how violence in Baghdad changed in the geographic catchment area of mosques associated with the Association of Muslim Scholars, Adnan al-Dulaimi’s Awqaf clerical network, and Moqtada al-Sadr’s movement as each group engages the formal political process at various times.