The author outlines how early Mormon settlers purchased land in the Oregon Trail area in Idaho. They brought with them both their religion and the knowledge of irrigation systems. In 1862, Congress promised inexpensive land to the settlers who would improve the land. However, the government restricted each person to 160 acres, and it was assumed that there would be sufficient rainfall. The land proved to be too arid, and Congress passed the Cary Act of 1894. Ira B. Perrine, a fruit grower who pushed for the Milner Dam, is also mentioned.