US 87 enters Wyoming from Colorado concurrent with Interstate 25, a concurrency that begins in
Raton, New Mexico, and the enter Cheyenne and intersect
Interstate 80. Between exits 12 and 17 is a concurrency with
US 85, which departs at
Ranchettes. I-25 and US
87 continue north to
Dwyer Junction, where it intersects
US 26 at exit 92 and it joins the concurrency. The three routes continue north to
Orin, where at exit 126 it intersects
US 18 and
US 20; US 18 terminates at the location but US
20 joins the route. I-25, US 20, US 26, and US 87 travel northward for to exit 160 east of
Glenrock, where US 20, US 26, and US 87 follow a segment separate from I-25. The routes rejoin I-25 in
Casper at exit 186 for , where US 20 and US 26 split westward at exit 189. US 87 remains concurrent with I-25 northward until its terminus with
Interstate 90 near
Buffalo, concluding its concurrency over three states (
unsigned in Colorado and
New Mexico). US 87 follows I-90 west for to exit 44, where it follows a section independent of another Interstate or U.S. highway, the only such section in Wyoming. A portion of US 87 was washed out in the late 1990s at the Massacre Hill Historic Site, so detour signs are posted directing US 87 traffic along
WYO 193 through
Story. US 87 is still officially designated through the disconnected washed out area; however the section is unsigned in favor of
WYO 346 to the south and
WYO 344 to the north of the washed out area. North of WYO 193
, US 87 signage resumes and it continues to
Sheridan and rejoins I-90 at exit 25. I-90 and US
87 share a concurrency
US 14 to exit 9 at
Ranchester, where US
14 splits west. I-90 and US
87 continue northward and crosses into Montana. ==History==