Sixteen species of odonates, representing 9.2% of Alabama's odonate fauna, were collected from flowing waters 10–450 m wide in the poorly surveyed Mobile/Tensaw Delta of Baldwin County over a one-year period. The number of species was positively correlated with the number of specimens per site, with sites nearest Mobile Bay having fewer species, possibly reflecting higher salinities. Odonate assemblages in large flows of the Delta are unpredictable in terms of species co-occurrence, and fit a model of non-equilibrium community structure.