These data were compiled as part of an ecological study of Sonora Mud Turtles and their interaction with non-native turtles at Montezuma Well in Yavapai County, Arizona. The data consist of observations and measurements of individual turtles captured during the study, and support analyses of population size and trends, general condition and health of the turtles, and female reproduction. Principal investigators for the study were Phil Rosen (1983 data), Matthew Malone and Steve Garber (1999 data) and Jeff Lovich and Charles Drost (data from 2007 through 2015). This dataset provides detailed capture data, measurements, and female reproductive status for the Sonora Mud Turtle population at Montezuma Well, which should be useful for comparisons with future studies of this same population, with other populations of Sonora Mud Turtles in other parts of the species' range, and with other turtle species.