SH-8 begins at the Washington state line, connecting with
Washington State Route 270 to
Pullman. Between the cities to the north is the
Pullman-Moscow Regional Airport. The two state highways comprise the "Moscow-Pullman Highway" in the between the university cities. In Moscow, Highway 8 runs east along the northern boundary of the
University of Idaho campus as Pullman Road (widened to five lanes in 1996–97), enters an
"S" curve, and becomes Third Street. It briefly overlaps
US 95, and runs south through the city center (one ways (since 1981): Jackson Street southbound and Washington Street northbound, a block on either side of Main). South of downtown, SH-8 branches east to become the "Troy Highway" and continues to
Troy, where it intersects
SH-99. East of Troy, SH-8 heads generally northeast, intersecting
SH-9 shortly before entering
Deary and overlapping
SH-3 there. From Deary, the overlapping highways run east and northeast to
Bovill, where they diverge. From Bovill, SH-8 heads south and southeast into
Clearwater County, then turns east and northeast into
Elk River, where it ends at the intersection of First and Main streets. There it links with Moscow's Paradise Path, which continues alongside the creek on the north and east edges of the UI campus; it connects to the Latah Trail in southeast Moscow and then travels east through open
Palouse country to Troy. ==Major intersections==