Forest Service data
The FSGeodata Clearinghouse is a pretty good source for Forest Service data. Individual National Forests may also have GIS data available from their web sites.
JAN 2016 EDIT: New FS clearinghouse link:
http://data.fs.usda.gov/geodata/http://svinetfc4.fs.fed.us/clearinghouse/index.htmlSelect Vector Data Gateway
Here is the procedure I use:
From tabs at top of screen select Zoom to Location > select Forest (NF) > select the NF of interest > press Submit. It will load an over view map of that NF.
The indented instructions are probably not needed, can likely go directly to download tab.
Click on the Layers/Legend tab on the right > click the Layers tab.
Click on the right arrow next to the Base Map Data to see layers available.
Clicking on a layer listing will turn it on or off.
Click refresh.
May need to zoom in to see some data layers.
Click the Download tab at the top > click Extract Layers.
Click the Extract Location tab. Select the Download radio button.
Click I have read the disclaimer…important detail.
Click on the right arrow next to the Base Map Data to see layers available. Turn on desired layers by clicking on them.
Click the left Select Item drop box to select a NF, then select the forest from the right drop box.
Click Submit.
It will display: Extracting Layers and Display a File Download dialog to download the zipped file.
The Extracting layers can take a few minutes.
When the file is unzipped this will create a .shp, .shx, and .dbf for each layer
Perry