The Uinta Mountains in north eastern Utah run east-west. The western end is approximately 50 miles east of Salt Lake City and they run about 150 miles east into Colorado. This is the only major east-west mountain range in the continental US.
The Capitan Mountain (home of Smokey Bear)near Capitan, NM also runs East-West. This rugged mountain is `10200 ft. A wilderness covers most of this mountain.
The Ouachita Mountains are a mountain range located in west central Arkansas and southeastern Oaklahoma. Unlike most other mountain ranges in the United States, the Ouachitas run east and west rather than north and south. Also, Ouachitas are distinctive in that volcanism, metamorphism, and intrustions are notably absent throughout most of the system.
The San Bernardino Mountains run for approximately 60 mi (100 km) east-west on the southern edge of the Mojave Desert in southwestern San Bernardino County.
The entire Transverse Range of California trend East and West. Santa Ynez, San Rafael Mountains, Sierra Madre, Topatopa Mountains, Santa Susana Mountains, etc, etc. The northern Channel Islands are also part of the Transverse Ranges.