Knowledge of biogeographic variation in Wolbachia infection rates and inferred susceptibility to infection among different mosquito taxa has fundamental implications for the design and successful application of Wolbachia-based vector-borne disease control strategies. Using a Wolbachia-specific polymerase chain reaction assay, we tested 14 North American mosquito species in five genera (Aedes, Anopheles, Culiseta, Culex, and Ochlerotatus) for Wolbachia infection. Wolbachia infections were only detected in members of the Culex pipiens (L.) species complex.