Interstate 35

I-35 starts at this traffic signal in Laredo, Texas

I-35 northbound begins at a traffic-signaled intersection with Bus. I-35-A in Laredo, Texas, just north of the Rio Grande and the international border between Mexico and the US. It has a 17-mile (27 km) concurrency with US 83. Through Webb, La Salle, and Frio counties, it has a mostly north-northeastern course, turning more northeasterly around Moore.[4] It then cuts across the corners of Medina and Atascosa counties before entering Bexar County and San Antonio.

I-35 is named the Pan Am Expressway in San Antonio. There, it has brief concurrencies with I-10 (with it US 87) and I-410, and it serves as the northern terminus of I-37. I-35 heads northeast out of the city toward the state capital, Austin.

In Austin, I-35 is the Interregional Highway and has a concurrency with US 290 through Downtown Austin.[5] Throughout Austin, elevated express lanes were constructed on either side of the original freeway. Prior to this expansion, this section included an at-grade railroad crossing, which is extremely unusual for a freeway. From Austin, I-35 goes through Round Rock, Temple, Pflugerville, and Waco. In Belton, south of Temple, it serves as the current eastern terminus for I-14. In Waco, I-35 is known as the Jack Kultgen Freeway, and begins its concurrency with US 77. The campuses of both the University of Texas at Austin and Baylor University are located adjacent to I-35.

I-35 then heads to Hillsboro, where it splits into I-35W and I-35E and runs through the Dallas–Fort Worth area. The official milemarkers, along with the route of US 77, follow I-35E through Dallas—I-35W, which is 85 miles (137 km) in length, carries its own mileage from Hillsboro to Denton, as though it were an I-35 loop. In Dallas, I-35E is the R.L. Thornton Freeway south of I-30, which picks up the name heading east. North of I-30, it is the Stemmons Freeway.

After passing through Dallas and Fort Worth, I-35's two forks rejoin each other in Denton near the University of North Texas campus. The unified Interstate then continues north to Gainesville before crossing the Red River into Oklahoma.

I-35 in Goldsby, Oklahoma, at milemarker 102

In Oklahoma, I-35 runs from the Red River at the Texas border to the Kansas state line near Braman. It passes through or adjacent to many of the state's major cities. From south to north, these cities include Ardmore, Pauls Valley, Purcell, Norman, Moore, Oklahoma City, and Edmond. In Downtown Oklahoma City, I-35 has a major junction with I-40 and spurs into I-235 through the north central inner city as heavy traffic follows through the city into the northern area of the state.

A view from the I-35 portion of the Kansas Turnpike, between mileposts 29 and 30

Between the Oklahoma state line and Emporia, I-35 is part of the Kansas Turnpike. This section of Interstate serves Wichita and passes through the Flint Hills area. At Emporia, I-35 branches off on its own alignment. This free section of I-35 provides access to Ottawa before entering the Kansas City Metropolitan Area, where it serves Johnson County and Kansas City, Kansas.

Of note on the route, at several points between Cassoday and Emporia in the Flint Hills, dirt driveways that provide direct access without a ramp, for cattle trucks, may be found in either direction along the highway.

BETO Junction is a highway intersection in Coffey County, Kansas, that is the intersection of US 75 and I-35. It derives its name from the four major cities nearest the intersection: Burlington, Emporia, Topeka, and Ottawa. It is located 16 miles (26 km) north of Burlington at exit 155. Historically, the intersection referred to as "BETO Junction" before I-35 was constructed was located on the old US 75 alignments two miles (3.2 km) south and two miles (3.2 km) east, near Waverly, Kansas.

Bond Bridge carries I-35 in Kansas City

I-35 enters Missouri two miles (3.2 km) southwest of Kansas City's Central Business District as a six-lane highway. After merging with Southwest Trafficway and Broadway, it becomes eight lanes and continues north to downtown Kansas City, where it serves as the west and north legs of the downtown freeway loop. Along the north edge of the loop, I-35 joins with I-70 immediately west of Broadway and carries six lanes of traffic with a speed limit of 45 mph (72 km/h). Upon leaving the loop, I-29 begins, concurrent with I-35. The two Interstates cross the Missouri River together on the Bond Bridge.

After crossing the river, I-29 and I-35 split. I-35 heads north to Cameron, Missouri, and then continues northward to the Iowa state line.

I-35 in Iowa, near exit 182. The town of Swaledale is about one mile (1.6 km) to the east.

In the southern sections of the state, I-35 is parallel to US 69 for much of its course.

In Des Moines, I-35 has a 12-mile (19 km) overlap with I-80. The concurrency takes place northwest of the downtown district of the city. At exit 127 of I-80, the overlap turns east and terminates at exit 137 via an interchange with I-235.

North of Des Moines, I-35 is mainly parallel with US 69, traversing a vast and rural area of Iowa.[6]

I-35 is part of the Avenue of the Saints between Clear Lake and St. Paul, Minnesota. A four-lane link has been completed between Clear Lake and I-380 in Waterloo, Iowa.

I-35's northern terminus is at this intersection with London Road (MN 61) in Duluth, Minnesota, with Lake Superior in the background.

At Medford, Minnesota, the on- and offramps lead to roundabouts rather than standard cross intersections.[7] This is the first site in the state linked to a major highway to use roundabouts.

I-35 splits again into I-35W and I-35E in the Minneapolis–Saint Paul area. The mile- and exit-numbering sequence continues along I-35E. At one sharp turn in I-35W near the junction with I-94, drivers are advised to slow to 35 mph (56 km/h) (although many drivers are able to maintain the speed limit of 55 mph (89 km/h)). It is not possible to go from westbound I-94 to northbound I-35W, from southbound I-35W to eastbound I-94, and vice versa, without resorting to surface streets.

On I-35E in Minnesota between MN 5 and I-94, in both directions, trucks weighing more than 9,000 pounds (4,100 kg) are banned from the freeway, and the speed limit drops to 45 mph (72 km/h). This section was not completed until the late 1980s (although the route was cleared and graded earlier) due to opposition from the historic Crocus Hill neighborhood, which sits only a few hundred feet from the alignment. The four-lane alignment, "parkway" design was a compromise. The truck bypass for this section is signed on I-494 and I-694 to the east of Saint Paul.

I-35 has an interchange with I-535/US 53 in Duluth, Minnesota, known locally as the "Can of Worms". This junction features a pair of left exits from I-35, a stoplight, and lane drops over the I-35 bridge.[8]

The national northern terminus of I-35 is at an intersection in eastern Duluth. Drivers' options include merging with London Road/MN 61 northbound, proceeding through the stop lights onto 26th Avenue East, or turning left onto London Road southbound.

I-29 and I-35

The proposed Trans-Texas Corridor toll-road project included one proposal (TTC-35) to primarily parallel I-35 from the Mexican border up to the Oklahoma border.[13] There are major disagreements as to what impact this parallel route would have on I-35 in terms of traffic, maintenance, and commerce.

The Trans-Texas Corridor was first proposed by Texas Governor Rick Perry in 2002. It consisted of a 1,200-foot (370 m) wide highway that also carried utilities such as electricity, petroleum, and water as well as railway track and fiberoptic cables.[14] In July 2007, US Representative Duncan Hunter successfully offered an amendment to House Resolution 3074, the FY2008 Transportation Appropriations Act, prohibiting the use of federal funds for Department of Transportation participation in the activities of the Security and Prosperity Partnership of North America (SPP). Hunter stated that: "Unfortunately, very little is known about the NAFTA Super Highway. This amendment will provide Congress the opportunity to exercise oversight of the highway, which remains a subject of question and uncertainty, and ensure that our safety and security will not be compromised in order to promote the business interests of our neighbors."[15] Fellow Republican Congressman and presidential candidate Ron Paul brought the issue to mainstream prominence during the December 2007 CNN–YouTube GOP debate, where he rejected the concept and also called it the NAFTA Superhighway after the North American Free Trade Agreement and, like Hunter, framed it within the ultimate goal of creating a North American Union.

In 2011, the Texas Legislature formally repealed its authority for the establishment and operation of the Trans-Texas Corridor with the passage of HB 1201.[16][17]