A multi-scale assessment of wildlife habitat connectivity and barriers to animal movement along 35 miles of Interstate 90 between Snoqualmie Pass and Cle Elum, Washington was conducted from January 1998 to March 2000. This assessment consisted of 5 components: 1) Landscape-scale Geographic Information System (GIS) "least-cost path" modeling to evaluate relative habitat linkage for 4 guilds of wildlife species; 2) GIS analysis of deer and elk road-kill distribution; 3) Automatic camera surveys to evaluate wildlife distribution in the vicinity of the highway; 4) Existing highway structure monitoring to document wildlife use of bridges and culverts; and 5) Winter snow tracking surveys to document animal distribution and highway crossing locations. The authors found that linkage areas identified by GIS habitat linkage modeling for high mobility habitat generalist species and moderate mobility late successional forest species corresponded to areas with high deer and elk road-kill density and frequent highway crossing documented during snow tracking. They identified 4 deer and elk road-kill concentration areas and evaluated the habitat characteristics of these areas. Automatic camera survey detection rates did not differ for camera stations more or less than 1 mile from the highway for most species, but did differ between different highway segments. Bridges and dry drainage culverts were used by 15 mammal taxa. However, medium and large carnivores commonly detected in the vicinity of the highway were not recorded in highway structures. During 250 miles of snow tracking surveys, the authors recorded 49 highway crossings by coyote, 13 by bobcat, and 5 by raccoon. Highway crossing locations recorded during snow tracking were clustered in distribution. Results of this study were used to identify areas of high landscape permeability for animal movement relative to adjacent areas along the highway corridor.