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
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 civilization.
Looking at these shaded relief maps, without the advantage of
roads and bridges, one can see the kinds of geologic challenges
the explorers encountered.
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
|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
|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
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 sources.