We describe an undocumented large population of Ferocactus emoryi (Engelmann) Orcutt that straddles the border of Pinal and Maricopa Counties at the southwestern base of Table Top Mesa and along Vekol Wash. This population consists of at least fifty and probably hundreds of individuals, including at least one small 10 x 15 cm individual. Further field work will be required to ascertain whether this population of F. emoryi is contiguous with (i) an extensive population on the western side of the Sand Tank Mountains, (ii) the main distribution of F. emoryi in southern Pima County, and (iii) the disjunct distribution in the Sierra Estrella. Based on our field observations, primary literature, and herbarium records, the range of F. emoryi in the United States is bounded to the east by the Baboquivari, Coyote, Quitojoa, Vekol, Table Top, and Estrella Mountains. The range is bounded to the north by the Gila River. The western boundary of the range is equivocal, with herbarium specimens from far western Pima County, but only written reports of F. emoryi from Yuma County. If the distribution of F. emoryi is found to be contiguous in Pima, Pinal, and Maricopa Counties, the distribution of F. emoryi in the United States is similar to that given in Nigel Taylor's systematic review of the genus, plus possibly peripheral populations as reported from Yuma County by Lyman Benson.