SH 142 begins in the west at its junction with US 285 mere feet outside the city limits of Romeo.

The highway passes through the San Luis Hills and over the Rio Grande.

The Manassa Dike is visible from the highway as it passes through the hills.

Overall, the highway has very little traffic, especially the section that passes through the San Luis Hills.

SH 142 connects the two river valleys (Conejos, Culebra Creek), passing through a high desert with little vegetation.