Interstate 45 (I-45) is a major Interstate Highway located entirely within the U.S. state of Texas. While most primary Interstate routes which have numbers ending in "5" are cross-country north–south routes, I-45 is comparatively short, with the entire route located within Texas. Additionally, it has the shortest length of all the primary Interstates that have numbers ending in a "5". It connects the cities of Dallas and Houston, continuing southeast from Houston to Galveston over the Galveston Causeway to the Gulf of Mexico.
U.S. Highway 181 is a south–north U.S. Highway located entirely in the state of Texas. Both termini are at Interstate 37, the road that it mainly parallels to the east. US 181 begins in Corpus Christi, Texas at mile marker 0 to the south, through south-central Texas to just south of San Antonio to the north, for a total length of 137 miles (220 km).
U.S. Route 80 or U.S. Highway 80 (US 80) is a major east–west United States Numbered Highway in the Southern United States, much of which was once part of the early auto trail known as the Dixie Overland Highway. As the "0" in the route number indicates, it was originally a cross-country route, from the Pacific Ocean to the Atlantic Ocean. Its original western terminus was at Historic US 101 in San Diego, California. However, the entire segment west of Dallas, Texas, has been decommissioned in favor of various Interstate Highways and state highways. Currently, the highway's western terminus is at an interchange with Interstate 30 (I-30) on the Dallas–Mesquite city line. Its eastern terminus is in Tybee Island, Georgia, near the Atlantic Ocean. Between Jonesville, Texas, and Kewanee, Mississippi, US 80 runs parallel to or concurrently with Interstate 20. It also currently runs through Dallas, Texas; Shreveport, Louisiana; Jackson, Mississippi; Montgomery, Alabama; Columbus, Georgia; Macon, Georgia; and Savannah, Georgia.
U.S. Route 75 is a north–south U.S. Highway that runs 1,239 miles (1,994 km) in the central United States. The highway's northern terminus is located at the Canadian border near Noyes, Minnesota, at a now-closed border crossing. From this point, the highway once continued farther north as Manitoba Highway 75. Its southern terminus is located at Interstate 30 (I-30) and Interstate 45 (I-45) in Dallas, Texas, where US 75 is known as North Central Expressway.
U.S. Route 290 is an east–west U.S. Highway located entirely within the state of Texas. Its western terminus is at Interstate 10 southeast of Segovia, and its eastern terminus is at Interstate 610 in northwest Houston. It is the main highway between Houston and Austin and is a cutoff for travelers wanting to bypass San Antonio on Interstate 10. Throughout its length west of Austin, US 290 cuts across mountainous hills comprising the Texas Hill Country and the Edwards Plateau; between Austin and Houston, the highway then travels through gradually hilly grasslands and pine forests comprising the Gulf Coastal Plains.
State Highway 35 is a 206.5-mile (332.3 km) state highway near the southeastern edge of Texas, United States, that is maintained by the Texas Department of Transportation (TxDOT). It runs primarily south–north, paralleling the Gulf of Mexico for much of its length, from a junction with Interstate 37 in Corpus Christi to Interstate 45 in southeastern Houston.
State Highway 6 (SH 6) runs from the Red River, the Texas–Oklahoma state line, to northwest of Galveston, where it is known as the Old Galveston Highway. In Sugar Land and Missouri City, it is known as Alvin-Sugarland Road and runs perpendicular to Interstate 69/U.S. Highway 59 (I-69/US 59). In the Houston area, it runs north to Farm to Market Road 1960 (FM 1960), then northwest along US 290 to Hempstead, and south to Westheimer Road and Addicks, and is known as Addicks Satsuma Road. In the Bryan–College Station area, it is known as the Earl Rudder Freeway. In Hearne, it is known as Market Street. In Calvert, it is known as Main Street. For most of its length, SH 6 is not a limited-access road. In 1997, the Texas Legislature designated SH 6 as the Texas Korean War Veterans Memorial Highway.
Texas state highways are a network of highways owned and maintained by the U.S. state of Texas. The Texas Department of Transportation (TxDOT) is the state agency responsible for the day-to-day operations and maintenance of the system. Texas has the largest state highway system, followed closely by North Carolina's state highway system. In addition to the nationally numbered Interstate Highways and U.S. Highways, the highway system consists of a main network of state highways, loops, spurs, and beltways that provide local access to the other highways. The system also includes a large network of farm to market roads that connect rural areas of the state with urban areas and the rest of the state highway system. The state also owns and maintains some park and recreational roads located near and within state and national parks, as well as recreational areas. All state highways, regardless of classification, are paved roads. The Old San Antonio Road, also known as the El Camino Real, is the oldest highway in the United States, first being blazed in 1691. The length of the highways varies from US 83's 893.4 miles (1,437.8 km) inside the state borders to Spur 200 at just 0.05 miles long.
Loop 9 is a proposed state highway that will be located on the southern fringes of the Dallas/Fort Worth Metroplex along the southern Dallas County line westward into northern Johnson County. It will measure about 45 miles (72 km) in length. Although it can be considered the southern counterpart to the President George Bush Turnpike (PGBT), it is actually being re-integrated into a plan for a broad outer loop that would extend far north of the metroplex. Loop 9 and the outer loop are part of a long-term plan to serve the expanding DFW population, forecasted to number 10 million circa 2040.
In the US state of Texas, Interstate 40 (I-40) runs west–east through the panhandle in the northwest part of the state. The only large city it passes through is Amarillo, where it meets the north end of I-27. The entire section of I-40 in Texas is designated as a Purple Heart Trail route.
State Highway 146 (SH 146) is a north–south highway in southeastern Texas beginning at I-45 near La Marque and Texas City. It then crosses over the Fred Hartman Bridge over the Houston Ship Channel which carries SH 146 traffic. It then continues north towards Dayton, where it meets US 90 and then heads north and terminates in Livingston at US 59.
State Highway 225 is an east–west freeway in the Houston area between the Interstate 610 Loop in Houston and State Highway 146/future State Highway 99 in La Porte. It is identified as the La Porte Freeway over its entire length. The freeway passes near several refineries, chemical plants, and tank farms as it passes through La Porte and Deer Park.
U.S. Highway 59 (US 59) in the U.S. state of Texas is named the Lloyd Bentsen Highway, after Lloyd Bentsen, former U.S. senator from Texas. In northern Houston, US 59, co-signed with Interstate 69 (I-69), is the Eastex Freeway. To the south, which is also co-signed with I-69, it is the Southwest Freeway. The stretch of the Southwest Freeway just west of The Loop was formerly one of the busiest freeways in North America, with a peak AADT of 371,000 in 1998.
Interstate business routes are roads connecting a central or commercial district of a city or town with an Interstate bypass. These roads typically follow along local streets often along a former U.S. Route or state highway that had been replaced by an Interstate. Interstate business route reassurance markers are signed as either loops or spurs using a green shield shaped sign and numbered like the shield of the parent Interstate highway.
All of the business loops within Texas are maintained by the Texas Department of Transportation (TxDOT). Interstate 20 (I-20) has 15 business loops in the state, all located in western Texas. Along I-20, TxDOT identifies each business route as Business Interstate 20 followed by an alphabetic suffix. Along Texas Interstates, the alphabetic suffixes on business route names ascend eastward and northward. There are gaps in the alphabetic values to allow for future system expansion. The alphabetic naming suffixes are included as small letters on the bottom of route shields.
All of the business loops are maintained by the Texas Department of Transportation (TxDOT). Interstate 45 (I-45) has four business loops in the state, all located in northern Texas. Along I-45, TxDOT identifies each business route as Business Interstate 45 followed by an alphabetic suffix. Along Texas Interstates, the alphabetic suffixes on business route names ascend eastward and northward. There are gaps in the alphabetic values to allow for future system expansion. The alphabetic naming suffixes are included as small letters on the bottom of route shields.
I-30 / I-45 / US 67 in Dallas 
US 69 / US 75 near Denison
