From the west, LA 123 begins at a T-intersection on
LA 8 located about east of
Colfax and east of
US 71 in
Grant Parish. The route heads northeast, winding through the thick piney woods of the
Kisatchie National Forest's Catahoula Ranger District. After , rural residences begin to line the highway, and LA 123 soon enters the village of
Dry Prong. At an intersection with Grove Street, the highway meets the eastern terminus of
LA 122, connecting with
Verda and
Montgomery. Shortly afterward, LA 123 crosses
US 167, an undivided four-lane highway connecting with the cities of
Winnfield and
Alexandria to the north and south, respectively. After crossing the
Kansas City Southern Railway (KCS) line at grade, LA 123 proceeds northeast out of Dry Prong and takes a serpentine path through the largely uninhabited pine forest. later, after a nearly right-angle curve in the roadway, LA 123 passes through a point known as
Breezy Hill. Here, it intersects
LA 524, a former alignment of
US 165 that connects to the modern alignment in either direction. LA 123 continues eastward for another to its own junction with US 165, a divided four-lane highway whose immediate destinations are
Georgetown to the north and
Pollock to the south. A local road named Grover Atwell Road continues straight ahead from this intersection to an area along the
Union Pacific Railroad (UP) line known as
Howcott. The posted speed limit is generally , reduced to through Dry Prong. ==History==