In the early 1920s, the La Harmonia Company began farming cotton in the floodplain of the Rio Grande. This steam engine was used to pump water from the Rio Grande to irrigate the cotton fields and other crops. The Morse engine was used to run the cotton gin. Originally, cotton was hauled to Marathon to be ginned, which proved costly and impractical. To save money, in 1923, a gin was built in Castolon. Ginning cotton removes the seeds, which decreases the weight and shipping costs.

In the first year of operation, 146 bales of cotton were ginned from cotton grown by La Harmonia Company tenant farmers. Later, when cotton was found to be a viable crop, farmers from Johnson’s Ranch to Lajitas were bringing their cotton to Castolon to be ginned. In 1925, the gin had its best year with 251 bales. The arrival of the Pink Boll worm in 1927 was the beginning of the end for cotton in the region. By 1942, La Harmonia Company was ginning its last cotton crop of a mere 54 bales.

This gin stood near Cottonwood Campground until 1978 when a flood swept most of it downstream. The foundation for the warehouse and remnant scraps of metal are still visible near the amphitheater.