Western terminus to Jonesboro From the west, LA 4 begins at an intersection with
US 71 at the extreme southwest corner of
Bienville Parish. It proceeds east as an undivided two-lane highway and runs along the
Red River Parish line for before curving to the northeast toward
Ringgold. After , it intersects
LA 790, which heads southeast to
US 371 at
Tullis. later, LA 4 enters Ringgold on Mill Street where it intersects
LA 154 (School Street). The two highways proceed in a concurrency to the town's main junction at US 371 (Military Road), which connects to
Minden on the north and
Coushatta on the south. After making a brief jog south onto US 371, LA 4 and LA 154 turn east onto Bienville Road. At the eastern edge of town, LA 154 branches off to the northeast through
Jamestown while LA 4 proceeds southeast for to
Castor. Here it intersects
LA 792, which also connects to Jamestown, and briefly turns southeast, continuing the route of that highway to the village's main junction. At a four-way intersection,
LA 153 continues the route southeast to
Ashland;
LA 507 proceeds southwest toward
Womack; and LA 4 turns northeast co-signed with LA 507 for one block until the latter turns north onto Kepler Road. Leaving Castor, LA 4 proceeds in a general eastern direction for where it intersects
LA 9 in an area known as
Lucky. The immediate destinations of LA 9 are
Bienville to the north and
Saline to the south. later, LA 4 intersects
LA 155, also connecting to LA 9 at Saline, and the two highways proceed in a concurrency to a point known as
Friendship. Here,
LA 501 heads south toward
Calvin, and shortly thereafter, LA 155 splits off to the north toward
Liberty Hill. Meanwhile, LA 4 curves to the southeast through
Danville, a point on the
Kansas City Southern Railway (KCS), and crosses the
Dugdemona River into
Jackson Parish later.
Jonesboro to Winnsboro inside the parish line, LA 4 enters
Jonesboro, the parish seat, and widens to an undivided four-lane highway. It then turns east from South Cooper Street onto East Main Street, a divided two-lane street, and passes through the center of town. After crossing the KCS tracks, LA 4 intersects the concurrent
US 167 and
LA 147. US 167 connects to
Ruston on the north and
Winnfield on the south. After this junction, LA 4 narrows to an undivided two-lane highway and continues due east out of town for to
Weston, where it intersects
LA 811 (Gladway Road) and, later,
LA 505. Following the latter intersection, LA 4 curves to the northeast for and crosses the
Caney Creek Reservoir before entering the town of
Chatham. Running through town on Shell Avenue, it intersects
LA 146, another route into Ruston, and curves to the southeast. It then intersects
LA 34, which heads to Winnfield on the south and the major city of
Monroe to the northeast. Continuing southeast for , LA 4 intersects
LA 499 at a point near
Hoods Mill and heads in a general eastward direction into
Caldwell Parish. After crossing the parish line, LA 4 curves to the southeast and intersects
LA 557 at a point known as
Vixen. later, LA 4 intersects
LA 846 at
Mount Pleasant. After a brief concurrency, LA 846 splits off to the north, running parallel to LA 4 toward the previous junction with LA 557. later, LA 4 intersects
LA 3239, a gravel road that connects to
LA 126 west of
Grayson. After another , LA 4 intersects
LA 850 at
Pulpwood Spur then curves to the northeast across the
Union Pacific Railroad (UP) tracks to
US 165 at
Banks Springs, just north of Grayson. LA 4 turns northeast to follow US 165, becoming an undivided four-lane highway (with middle turning lane) into
Columbia, the parish seat, intersecting
LA 849 on the way. In Columbia, US 165 and LA 4 cross a high-level bridge over the
Ouachita River, after which LA 4 resumes its eastward course as an undivided two-lane highway while US 165 continues north toward Monroe. Opposite a bend in the river, LA 4 intersects
LA 133 and curves to the southeast, running roughly parallel to the river for . LA 4 then turns back to the east while
LA 559 continues south along the river. later, LA 4 crosses the
Boeuf River into
Franklin Parish after passing through the
Boeuf Wildlife Management Area. Continuing east for , LA 4 reaches
LA 135, the first of three junctions in an area known as
Fort Necessity. Shortly afterward,
LA 562 heads south and loops to the east across
Turkey Creek Lake to
Wisner, and finally,
LA 128 heads east to
Gilbert on
US 425/
LA 15. At this last junction, LA 4 curves to the northeast toward
Winnsboro. After , LA 4 intersects
LA 865 at a point known as
Brownell, followed later by
LA 3201 (Riser Road), a connector to US 425/LA 15 on the south edge of Winnsboro.
Winnsboro to Newellton LA 4 enters Winnsboro, which serves as the parish seat, and runs along Prairie Road. LA 4 then reaches the main thoroughfare, Front Street, an undivided four-lane roadway (with middle turning lane) and part of the concurrent US 425 and LA 15. LA 4 turns northwest onto Front Street, adding to the concurrency for a few blocks, to a four-way intersection where US 425 and LA 15 continue north toward
Bastrop and Monroe, respectively;
LA 130 heads west along Taylor Avenue; and LA 4 takes a sharp turn east onto Kinloch Street, becoming an undivided two-lane highway once again. This intersection also marks the western terminus of LA 17, which follows LA 4 east out of Winnsboro. Before exiting the city, LA 4 and LA 17 intersect the northern segment of LA 865 (Pine Street) and
LA 864 (Loop Road), another connector to US 425/LA 15. Shortly after crossing the city limits, LA 17 splits off to the north toward
Crowville. ==History==