We studied the morphological characters of the keeled earless lizard, Holbrookia propinqua, in Guadalupe County, Texas, near its type locality (Wilson County, Texas) and at the northern extension of its range. Adults of this population were similar to those of other mainland populations but significantly smaller than adults of coastal island populations. Juveniles of the population in Guadalupe County and a coastal population showed no significant differences in size. Tail length of males did not differ among mainland populations but differed significantly from those of the island populations.