You are at the top of a tree-like hierarchy of categories that describe
the sciences, topics, and methods of USGS.
From here, you can move around the "tree" to explore the categories -- their
definitions, how they're used, broader or narrower terms, etc. -- and find
selected USGS web pages that contain more infomation about a category.
Since most USGS information is spatial, you also can use the boxes on
the right to specify a location,
and the pages will be selected based upon the chosen category and location.
Start by choosing one of the high-level categories below:
