Where can I find bathymetric data?

The USGS has run bathymetric surveys for many marine areas, as well as for rivers and lakes in the US, including Yellowstone Lake, Crater Lake, and Lake Tahoe. Information and data from these studies can be found on this USGS Web site.

NOAA is the main source of bathymetric data for the world at their Bathymetry and Global Relief Web site.