In-stream habitat data include measurements of a variety of physical and aquatic stream attributes that collectively reveal a great deal about stream condition for salmonids and trout. Characterizing and inventorying the physical conditions that define stream habitat for salmonids is an important part of the habitat restoration process. The California Department of Fish and Wildlife (CDFW) collects data on a number of physical attributes of streams and classifies these streams by one of several habitat types. The in-stream habitat data collection process involves two distinct steps; identifying channel type and assigning a habitat type. These in-stream habitat data are used for a variety of purposes including analysis of stream suitability for supporting salmonid populations, as part of larger and more complex watershed assessments, and to establish baseline conditions against which future assessments can measure change. They are a critical part of determining restoration priorities and identifying salmonid refugia. The California Salmonid Stream Habitat Restoration Manual published by the CDFW, describes the process of using in-stream habitat data and other data and information for identifying streams with restoration potential and working through the stream restoration process.The objective of stream inventory reports are to document the current habitat conditions and recommend options for the potential enhancement of salmonid habitat. Recommendations for habitat improvement activities are based upon target habitat values suitable for salmonids in California's streams.