U.S. Highway 171 (US 171) is a part of the United States Numbered Highway System and the only route within that system currently located entirely within the state of Louisiana. It spans in a north–south direction from the junction of US 90 and Louisiana Highway 14 (LA 14) in Lake Charles to the junction of US 79/US 80 and LA 3094 in Shreveport.
As its designation indicates, US 171 is numbered as a spur of US 71, the principal north–south U.S. Highway through Shreveport, though they technically do not intersect. US 171 traverses six of the seven parishes along the Texas state line, the only exception being Cameron Parish located on the Gulf of Mexico south of Lake Charles. The route connects all six parish seats as it travels through the thick pine forests of western Louisiana on a wide four-lane right-of-way. The northern half of the route serves as the only major north–south corridor between Interstate 49 (I-49) to the east and the Toledo Bend Reservoir along the state line to the west. Between the metropolitan areas at each terminus, US 171 passes through the smaller cities of DeRidder, Leesville, and Mansfield, as well as the towns of Rosepine, Many, Zwolle, and Stonewall. Along the way, the highway has interchanges with many of the state's major east–west routes, including Interstate 10 (I-10), US 190, LA 28, US 84, and I-20.
US 171 was created as one of the original routes of the numbered U.S. Highway system in November 1926. Its only major alignment change occurred in 1937, when the highway was shifted from what is now LA 175 between Many and Mansfield. Improvements over the years have included the paving of the entire route during the early 1930s, the elimination of many at-grade railroad crossings during the remainder of the decade, and the widening of the highway to four lanes through its urban areas during the 1960s and 1970s. Four-laning of the entire route was accomplished between 1990 and 2010 via the state's massive TIMED program with the goal of improving safety and promoting economic development along the corridor.
The route carries several honorary designations, primarily that of the Purple Heart Highway in tribute to all recipients of the Purple Heart military decoration. The route has long been associated with the U.S. Armed Forces due to its proximity to at least four military bases active during the World Wars, the lone survivor of which is Fort Polk near Leesville.
Route description
Lake Charles to Leesville
From the south, US 171 begins at a junction with US 90 (Fruge Street) and LA 14 (South Martin Luther King Highway), in Lake Charles, the largest city in Calcasieu Parish and southwestern Louisiana. Traveling about east of the downtown area, US 171 continues the route of LA 14 northward along North Martin Luther King Highway, initially as a divided four-lane highway. After immediately crossing over the BNSF and Union Pacific (UP) railroad lines, N. Martin Luther King passes through a partial cloverleaf interchange with I-10 at exit 33, connecting with Beaumont, Texas to the west and Lafayette to the east. The highway gains a center turning lane and an additional northbound travel lane throughout the commercial corridor north of the interstate. Upon exiting Lake Charles, US 171 traverses a strip of wetlands with twin-span bridges over two navigable waterways, English Bayou and the Calcasieu River. After crossing the latter, the roadway remains elevated until reaching the unincorporated suburb of Moss Bluff. A junction here with LA 378 (Sam Houston Jones Parkway) leads west to Sam Houston Jones State Park and the nearby city of Westlake. US 171 maintains a combination of single and double center lanes through Moss Bluff, dropping the N. Martin Luther King Hwy signage as it passes just north of central Moses Bluff. As the surroundings become less developed, the right-of-way widens to accommodate a broad, grassy median.