Because you are relatively close to Mexico and the size of the coin is about that of a US quarter,I'm leaning towards a 1/4 real, copper, from the state of Chihuahua. The US quarter has a diameter of just over 24 mm. There were three varieties of the Mexican coin; one at 24mm and 2 at 26mm. The obverse legend of the '24' read: Departmento de Chihuahua. Another reads: Estado Libre de Chihuahua; and the third reads: Estado de Chihuahua. The reverse image was the value on two lines within a double wreath of palm branches (what is more clearly seen in your pics).
Don.....