It was over 225 years ago that the Anza Expedition
traveled an overland route by horse and by foot leading from the
Sonoran desert in today's northern Mexico to the San Francisco Bay
(for more on this, see Historical
In geographical time, that was not really very long ago. Anza and
his entourage saw the same mountains we see today, rising from the
same deserts and the same coastal areas. Some aspects of the landscape
of today is, however, somewhat different from the one Anza encountered,
changed by roads, dams, and buildings. Even rivers have been re-routed
and their flows increased or decreased to meet the needs of modern
Looking at these shaded relief maps, without the advantage of roads
and bridges, one can see the kinds of geologic challenges the explorers
For example, the differences between today's landscape and that
of 1775 is most noticeable in the San Francisco bay region. The
bay has changed greatly over the years, partly due to human engineering
and partly due to natural influences. To see how the bay looked
around 1775, go to the San Francisco Estuary Institute's EcoAtlas.
The Four Regions
The maps are divided into four main regions, subdivided to show
In each of these regions, significant events took place. Most of
these four maps are also subdivided into smaller sections that you
may choose among.
Layers showing modern features such as roads, towns and modern streams
can be turned on and off using the buttons below the maps. These
modern features were drawn from current GIS data, and provide some
indication of where the historic trail was in relation to modern
landmarks that we know. Each map is made up of at least three layer
selections. The shaded relief shows elevation and is always visible.
The Historic Trail is featured in gold, and follows the path where
scholars have determined it probably was.
Links to More Information
The expedition campsites are marked by number, and linked to information
on a separate page. The map links (seen when your mouse rolls over
them) provide information about placenames and locations, and connect
you to the full text of the original diaries, pictures, other maps,
and organizing resources such as a chronology of events, a list
of campsites, and a list of the people on the journey.
To get a better view of the maps, zoom in by right clicking (PC),
or Cmd-clicking (Mac), and selecting "zoom in."
These relief maps were created using modern GIS data, but for comparison,
we have provided links to historical geographic maps when possible.
To create the shaded relief, we used modern GIS data from various