In 1881, Texas and Pacific Railroad surveyor Thomas John (Pat) Monahan, seeking water for trains crossing the western plains and frustrated by the delays and expense of hauling water from Big Spring to railroad crews, stopped at a town later known as Monahans and dug a well that struck water. Construction continued later that year until the well reached 53 feet deep and 18 feet in diameter, with 20 feet of inflowing water, and the town added a pump station and two water tanks. The well supplied both the town and passing trains, and it also carried gypsum that the town mined and shipped to eastern markets for fertilizer production. By the 1890s, Monahan had built a grocery store, general store, boarding house, and hotel for prospectors and land agents, and over time Monahans developed as a hub for ranching, farming, and oil in west Texas. Although the surrounding town had originally been named Trueheart and the land around the railroad was called Monahan's Well, the Post Office dropped both names in 1891 and established the whole region as Monahans. As electric wells replaced older wells in the 1930s, the well was eventually filled with gravel, but the discovery of water there was integral to opening the western plains to railroad expansion.