These data represent reproductive ecology characteristics for 4 species of mature female turtles captured at Elephant Butte Reservoir on the Rio Grande River in New Mexico, during two field survey periods in June 2012 and 2013. Data were collected on female reproductive ecology including clutch size, egg size, timing of egg production, and the percentage of reproductive females using X-radiography. The purpose of these data are to add to the deficient information on the reproductive ecology of four turtle species at the Elephant Butte Reservoir on the Rio Grande and Black River in New Mexico. Data contained in this worksheet were analyzed to determine clutch and egg sizes for four native species of turtles (Apalone spinifera, Chrysemys picta, Pseudemys gorzugi, and Trachemys gaigeae gaigeae).