During a multi-year study of the rare Blair's fencing crayfish (Faxonella blairi Hayes and Reimer), we made 87 collections in 10 counties throughout the West Gulf Coastal Plain of southwestern Arkansas. Intensive searches throughout these counties revealed the presence of 36 new populations of F. blairi in Little River, Miller, and Sevier counties. In each of these counties, F. blairi was found to be a locally abundant crayfish. New county records from museum collections were documented for Columbia and Howard counties, Arkansas, and Cass County, Texas. Additionally, we surveyed genetic variation in F. blairi and found them to be a monophyletic group with a sister relationship to Faxonella clypeata but with clear genetic distinctiveness from this sister taxon. There was modest genetic variation within Arkansas, and this genetic variation was greater than that across Arkansas, Oklahoma, and Texas for F. blairi. Faxonella blairi should be considered as currently stable due to its more widespread distribution than previously believed and general abundance throughout its range in southwestern Arkansas.