Route 15W or Highway 15W may refer to:
Interstate 86 (I-86) is an east–west intrastate Interstate Highway located entirely within the state of Idaho. It runs approximately 63 miles (101 km) from an intersection with I-84 east of Declo in rural Cassia County, to an intersection with I-15 in Chubbuck, just north of Pocatello. The highway is part of the main route from Boise and Twin Falls to Idaho Falls and the upper Snake River region.
K-15 is a 257.141-mile-long (413.828 km) north–south state highway in the U.S. State of Kansas. Originating at the Oklahoma state line as a continuation of State Highway 18 and continuing to the Nebraska state line where it continues as Nebraska Highway 15. Throughout Kansas, it is signed as the Eisenhower Memorial Highway due to its route through Abilene, where the Eisenhower Memorial Museum and Library is located.