Texas The southern terminus is in
Del Rio, Texas at an intersection with
U.S. Route 90. It goes north of town co-signed with
U.S. Route 277 for 20 miles (32 km). After splitting off, it enters
Edwards County and
Carta Valley. It meets
SH 55 at the county seat,
Rocksprings, before serving as the western terminus of
SH 41. About 20 miles north of Rocksprings, the route meets with the headwaters of the South
Llano River, which follows the route into
Junction, Texas. It heads northeast into
Kimble County, crossing the county line near
Telegraph. At Junction, it meets both
Interstate 10 and
US 83. It then continues northeast through
London, extreme southeastern
Menard County, and
Mason County. In Mason County, US 377 passes through
Streeter before forming a
concurrency with
SH 29 near
Grit. In
Mason, SH 29 splits off to its own alignment while US 377 turns north to join
U.S. Route 87. US 87/377 head north together into
Brady, where they meet
US 190, the southern terminus of
US 283, and
SH 71. US 377 splits off to the north and heads to
Mercury and crosses the
Colorado River near
Winchell. In
Brownwood, US 377 joins with
U.S. Route 67, following its routing all the way to
Stephenville, where US 377 splits off on its own again. US 377 then enters
Hood County, where it passes through the county seat,
Granbury. It cuts the corners of both
Johnson County and
Parker County before entering
Tarrant County and the
Dallas-Fort Worth Metroplex. US 377 crosses
Interstate 20 at exit 429A in
Benbrook. It then enters
Fort Worth proper, meeting
SH 183 and
Spur 580. It runs northeast on Camp Bowie Blvd. to
Interstate 30, which it begins a concurrency with. At the
Interstate 35W junction, it heads north along that highway before splitting off at Exit 52A (Belknap St.). It heads due north at the Denton Highway and continues to run parallel to I-35W through many Fort Worth suburbs, including
Haltom City,
Watauga,
Keller,
Westlake,
Roanoke, and
Argyle. In
Denton, it joins
Interstate 35E via a "wrong-way" concurrency to Loop 288 (as of January 2025), then has a concurrency with Loop 288 before joining
US 380 through the eastern portion of Denton into
Crossroads; US 377 had previously crossed I-35E before its concurrency with US 380 north of Downtown Denton.. After splitting from US 380, US 377 runs through
Crossroads and north into
Krugerville. It continues through
Aubrey, through
Pilot Point,
Tioga, and
Collinsville, before having an interchange with
US 82 at
Whitesboro. It the heads north to cross
Lake Texoma (the
Red River) into Oklahoma.
Oklahoma US 377 is co-signed with
State Highway 99 for its entire
Oklahoma length. US 377's first junction within Oklahoma is with
SH-32 west of
Kingston. The first town that US 377/SH-99 pass through is
Madill, where the two highways meet
US 70 and
State Highway 199. The next town after that is
Tishomingo, where there is a brief concurrency with
SH-22. US 377/SH-99 run north from Tishomingo, having a one-mile (1.6 km) three-route concurrency with
SH-7 before meeting
State Highway 3 southeast of
Ada. US 377/SH-99 run around the east and north sides of town. On the north side of Ada, SH-3E joins the concurrency. After leaving Ada, US 377/SH-3E/99 pass through
Byng. The three highways cross the
Canadian River just south of a junction that serves as the eastern terminus of
SH-39 and the western terminus of
SH-56. North of
Bowlegs, SH-59 joins with the other routes briefly. The next major town is
Seminole, where the highways meet
SH-9, and SH-3E splits off. US 377/SH-99 cross
I-40 at Exit 200. The highways have a junction with
US 62 in
Prague. As of 2007, the highway's northern terminus is in
Stroud, Oklahoma at an indeterminate point somewhere between old
Route 66 (now
Oklahoma State Highway 66) and modern
Interstate 44. SH-99 continues north into
Kansas. ==History==