Colorado’s dry eastern plains make irrigation the permanent limit on arable farming.

Evidence

This, the youngest State in the Union, a Territory until quite recently, has an area of about 68,000,000 acres, a great portion of which, though rich in mineral wealth, is worthless either for stock or arable farming, and the other or eastern part is so dry that crops can only be grown profitably where irrigation is possible. … The necessity for irrigation, however, will always bar the way to an indefinite extension of the area of arable farms. — Isabella L. Bird, A Lady’s Life in the Rocky Mountains, 166

Categorization

• XREF: Connects to her recurring attention to aridity and water as the defining constraint of the American West.