The valley of the Chira river runs for about a hundred and fifty kilometers, from the Andes to the Pacific, through the department of Piura in the north of Peru. For most of the year, the rain forgets to fall there. The soil is alluvial — washed down from the mountains over millennia, deposited in fans across the valley floor, fine-grained and porous enough that water and roots agree to coexist in it without much friction. The sun rises early and sets late, and when it shines, it shines without interruption.
These three conditions — sun, soil, water — are what cotton needs to grow well. They are also, when assembled in the right proportion, what cotton needs to grow long.
There are perhaps a dozen places on Earth where the proportion is right. Egypt's Nile Delta. The San Joaquin Valley of California. The Indus Plain. A handful of valleys in northwestern China. And the coast of northern Peru — Piura, Lambayeque, the dry Pacific lowlands where cotton has been planted, by hand and machine, since long before the Spanish arrived.
Each of these places makes a different kind of cotton. The cotton of Piura is its own answer.
There is a tendency, in writing about origin, to romanticize the place into a set of postcards. The blue sky, the patient farmer, the field at golden hour. Piura does not need that treatment. It is hot, it is dusty, the work is hard, the weather is sometimes punishing. The cotton it produces is not romantic; it is real.
But there is something about the specificity of a place that, when honored, redeems the cliché of "origin". Pima cotton is not from "South America". It is from the valleys north of the Sechura desert, irrigated by canals that were laid down in the colonial period and rebuilt in the twentieth century, harvested by people who learned the work from their parents. The fiber carries that geography in its length, in its finess, in its quiet brightness.
We use it because no fiber on earth is exactly like it. We name the place because the fiber is, in the end, indistinguishable from the place that grows it.