These prior WGS studies have analyzed outbreaks within a specific area but none have evaluated the population genomics of all 17 Lp serogroups and the 18 other Legionella species associated with human disease, albeit rarely, to understand their evolutionary strategies. Here, we compared the dynamics of genome change both within Lp and across the Legionella genus. Our genomics analyses encompassed 43 species and serogroups of Legionella, including 33 strains (Lp serogroups 2 through 17, and 17 other Legionella species) sequenced in the present study along with nine Lp1 strains and L. longbeachae that were publically available.