The route travels to the southeast, passing a section of the Lower Rio Grande Valley National Wildlife Refuge, before turning to a more easterly path and crossing into Willacy County. SH 186 runs along Hidalgo Avenue in Raymondville, where it crosses  I-69E / US 77.
The route travels southeast, passing through a section of the Lower Rio Grande Valley National Wildlife Refuge, before turning to an easterly path and crossing into Willacy County. SH 186 runs along Hidalgo Avenue in Raymondville, where it crosses I-69E / US 77.