The highway begins at the junction with NM 28 south of Chamberino.

The road heads east-northeast through pecan orchards and fields of Mesilla Valley and after approximately 0.7 miles crosses La Union Main Canal.

At 1.05 miles (1.69 km) NM 186 passes by Anthony Country Club, then crosses the Rio Grande over a 482.0-foot-long (146.9 m) bridge, built in 1957.

NM 186 reaches its eastern terminus at intersection with FL 5872 (Levee Road) right after crossing the river.

[2] The entire route is in Doña Ana County.