State Highway 18 (SH 18) is a state highway in the U.S. state of Texas maintained by the Texas Department of Transportation (TxDOT) that runs from Fort Stockton in western Texas to the New Mexico state line between Kermit and Jal, New Mexico. This route was designated in 1958 over the northern half of what was previously SH 82.

SH 18 begins at Fort Stockton at an intersection with Business Interstate 10 and US 285. Heading north, it soon intersects Interstate 10 and US 67, which is in concurrency with the interstate. It continues traveling north through oil fields and rural ranch land. 25 miles north of Fort Stockton, SH 18 intersects Farm to Market Road 1450. The highway continues north and enters Grandfalls. In Grandfalls, the highway intersects SH 329 and Farm to Market Road 11. The highway continues north, intersecting Farm to Market Road 1776, Farm to Market Road 1233, Loop 464, and Interstate 20 before reaching Monahans. In Monahans SH 18 intersects Business Interstate 20 and continues northwest, making a second interchange with SH 464. Eight miles northwest of Monahans, the highway intersects Farm to Market Road 1219. SH 18 continues in a slightly northwest direction toward Kermit, making an interchange with Farm to Market Road 1232 along the way. In Kermit the highway has an intersection with SH 302 and a slight western concurrency with SH 115 before continuing to head northwest out of Kermit. The highway ends at the New Mexico state line, where the road becomes New Mexico State Road 18.

The current routing was originally planned as State Highway 17 as recently as 1922. On August 21, 1923, the SH 17 designation has been transferred to the routing of SH 17A, while this route was renumbered as SH 82. On February 27, 1958, the route was again renumbered as SH 18, to coordinate with the connecting New Mexico Highway 18 to the north.

SH 18 was one of the first 25 Texas state routes proposed on June 21, 1917, overlaid on the Albany-Bronco Highway. The original proposal was a route through the Southern Plains from Bronco in Yoakum County to Lubbock, then southeast to Albany. On December 20, 1917, SH 18 had extended southeast to Cisco and replaced SH 36 to Waco. By 1919, SH 18 was rerouted through Eastland. On August 21, 1923, the route had been changed significantly. The section of the route from Spur to Albany was intact, but the previous westward route veered northward instead to Turkey, with the old route being renumbered to SH 53. The section from Albany to Cisco became part of rerouted SH 23, the section from Cisco to Eastland was already part of SH 1, so that section was cancelled, and the section from Eastland to Waco became part of the new SH 67. SH 18 was instead extended northeast to Memphis. On November 19, 1923, the section of SH 18 from Turkey to Memphis was cancelled, and SH 18 was rerouted east to Estelline instead. On July 13, 1925, a split from Aspermont to Anson was added. This split became part of SH 4 on December 6, 1927. On October 22, 1935, SH 18 Loop was designated through Roaring Springs. On December 22, 1936, the section from Turkey to Estelline became part of SH 86. On May 24, 1938, it was extended farther northward to the Oklahoma state line, overtaking SH 88 from Turkey to Oklahoma. On January 6, 1939, two SH 18 Spur routes were designated to Spur and Peacock. On September 26, 1939, the portion from Matador to Albany was reassigned to U.S. Highway 62, SH 70, and U.S. Highway 380. The two SH 18 Spur routes were renumbered as Spur 21 (Spur) and Spur 22 (Peacock). SH 18 Loop was redesignated as Loop 42. SH 18 was extended further north to Perryton on May 21, 1940, and on October 10, 1947, became part of SH 70 when SH 70 was extended into Matador from the south due to the rerouting of U.S. Highway 62 off of this road.

SH 18A was an alternate route along SH 18 proposed on August 19, 1918. It covered a shorter route between Spur and Crosbyton during the 1920s.

SH 18B was a more southerly route proposed on January 23, 1919. It was to branch off from SH 18 in Brownfield, travel southeast to Lamesa, then run due east to Albany. It is unknown if it had been built before being renumbered on August 21, 1923, as SH 83, with the section from Lamesa to Brownfield cancelled.

County	Location	mi	km	Destinations	Notes
Pecos	Fort Stockton	0.0	0.0	I-10 BL / US 285 (West Dickinson Boulevard)	Southern terminus
		0.9	1.4	I-10 / US 67 – El Paso, Ozona	I-10 exit 259B
	​	24.6	39.6	FM 1450 to FM 1053 – Pecos
	​	28.0	45.1	RM 2593 east – Reservoir
Ward	Grandfalls	31.6	50.9	FM 11 east – Imperial
		31.8	51.2	SH 329 east (1st Street) – Crane
	Royalty	34.3	55.2	FM 1219 north – Wickett
	​	42.0	67.6	FM 1776 south – Coyanosa
	​	44.6	71.8	FM 1233 east to US 385
	​	45.9	73.9	Loop 464 north (truck route) to SH 18 north / I-20
	Monahans	48.6	78.2	I-20 – Pecos, Odessa	I-20 exit 80
		49.9	80.3	I-20 BL (Sealy Street)
	​	52.4	84.3	Loop 464 south (truck route) to I-20 / I-20 BL
	​	57.5	92.5	FM 1219 south – Wickett
Winkler	​	67.3	108.3	FM 1232 west – Wink
	Kermit	72.2	116.2	SH 302 (Jim Sharp Boulevard / truck route) – Mentone, Odessa
		73.0	117.5	SH 115 north (East Austin Street)	south end of SH 115 overlap
		73.2	117.8	SH 115 south (West Austin Street / truck route) – Wink	north end of SH 115 overlap
	​	77.5	124.7	FM 874 to SH 115 / SH 302
	​	83.7	134.7	NM 18 north – Jal	Continuation into New Mexico
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

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Geographic data related to Texas State Highway 18 at OpenStreetMap