IHAVE JUST SPENT several days exploring Arizona's borderlands and, as always, they have proved to be full of beauty and surprise.

The beauty is everywhere, and is often dramatic and stark, as when we walked out of a restaurant near Tubac and faced a jagged range of peaks etched against a still-bright sky long after sunset.

Surprises abound, too. At an old print shop, a local historian mentioned in passing that the Anza Trail passes just below Tubac, following a lovely little woodland stream.

This wouldn't mean anything if I hadn't been to Anza-Borrego Desert State Park in California early this year. There, I learned of a Spanish expedition led by Capt. Juan Batista de Anza in the 1770s, from northern Mexico through deserts to the coast. They named their new home San Francisco.

Brief later research failed to establish definitively many details of de Anza's overland expeditions, but he was clearly a major figure in Spanish explorations and settlement of northern California.

One exploration involved a large number of civilian colonists, possibly departing from Tubac in about 1776 and arriving in the Bay area months later. The number of men, women and children on this torturous trip is hard to nail down but probably exceeded 150. All but one survived the trek--made entirely on foot--through North America's harshest desert terrain (the Sonoran and Mojave deserts).

The most significant California expedition appears to have set out from Tubac Presidio, the first European settlement in what is now Arizona, in 1752, and the site of Arizona's first state park.

So although I came to learn about the first printing press and newspaper in the Arizona Territory, I discovered the origins of land settlement hundreds of miles away, on the Pacific Coast.

Several locals told me that de Anza's Trail was a few blocks away. I set out walking past quirky, colorful homes and a cattle lot and horse farm.

There, at the edge of a dense, dark woods, was a small sign: "ANZA TRAIL."