By Daniel Covarrubias, Ph.D., and Gerry Schwebel 

In the heartland of the United States, a continuous stretch of asphalt spans from Laredo, Texas, to Duluth, Minnesota, serving as a symbolic connector that unites the nation's central region.  

This is Interstate 35, a 1,568-mile behemoth that serves as a vital artery for trade, commerce, and cultural exchange. But long before eighteen-wheelers thundered along its lanes, this corridor was shaped by the steady plod of cattle hooves and the dreams of pioneers seeking fortune in the untamed West. 

The story of I-35 is not just one of concrete and steel but a tale that embodies the profound essence of America's heartland. It's a narrative that spans centuries, from dusty cattle trails to the contemporary superhighway we know today. To truly understand I-35's significance, we must look back to its humble beginnings and trace its evolution through the shifting dynamics of American commerce and transportation. 

From Hoofbeats to Horsepower: The Cattle Trail Legacy 

In the decades following the American Civil War, the American West was a land of opportunity, particularly in the cattle industry. Vast herds of longhorns roamed the plains of Texas, waiting to be driven north to the hungry markets of the Midwest and East. The inception of the legendary cattle trails—the Shawnee, the Chisholm, and the Great Western—served as pivotal pathways through the wilderness, ultimately shaping the route of Interstate 35. 

The Shawnee Trail, also known as the Texas Road, was the earliest significant cattle trail. It originated around San Antonio, with cattle collected there and driven northward through Austin, Waco, and Dallas before continuing into Missouri. This early cattle trail laid the groundwork for what would become the eastern fork of I-35 through Dallas, predating the more famous Chisholm Trail. 

The Chisholm Trail, which emerged later but attained prominence as the most renowned of these routes, stretched from south-central Texas northward through Oklahoma and into Kansas. Its trajectory closely approximates the contemporary I-35, connecting cities such as Austin, Fort Worth, and Oklahoma City—urban centers whose very existence is indebted to their position along this historic route. The trail served as a lifeline for the post-Civil War South, allowing Texas ranchers to move their cattle to railheads in Kansas, where they could be shipped to eastern markets. 

While not directly aligned with I-35, the Great Western Trail ran west of and roughly parallel to the Chisholm Trail. Originating near Brownsville in South Texas, it extended northwestward through Texas to Dodge City, Kansas. Although not directly along I-35's route, its southern origin near the Rio Grande Valley foreshadows the highway's future role in connecting the US-Mexico border region to northern markets. 

These trails were more than mere paths for moving livestock; they were the seeds of future commerce, catalyzing the establishment of towns and trading posts that would evolve into the cities we know today. The economic patterns established by these cattle drives, characterized by the northward movement of goods and the emergence of key trading hubs, demonstrated remarkable prescience, foreshadowing the role played by I-35 in the 20th and 21st centuries. 

Laredo: From Frontier Outpost to International Gateway 

At the southern end of this highway lies Laredo, a city whose story is inextricably linked with that of I-35. Long before it became the bustling port of entry we know today, Laredo was a critical juncture for the cattle industry. Situated on the Rio Grande, it served as a gathering point for cattle from ranches in South Texas and northern Mexico, making it a natural starting point for the long journey north. 

Laredo's position as a crossroads of international trade was established well before the concept of I-35 was even conceived. Straddling the Rio Grande and serving as a natural gateway between two nations, Laredo's unique geographic location made it a vital hub for cross-border commerce. This strategic position, coupled with the city's long-standing role in facilitating the movement of goods between the U.S. and Mexico, made Laredo the logical choice for the southern terminus of a major north-south highway. The decision to anchor I-35 in Laredo, which was made several decades ago, has only gained significance as cross-border trade has expanded in the aftermath of agreements such as NAFTA and its successor, the USMCA. 

Today, Laredo stands as a testament to the enduring significance of location in trade and transportation. The city processes over 40% of all U.S.-Mexico trade, with nearly 20,000 trucks crossing its bridges daily. This modern-day trade prosperity is a direct descendant of those early cattle drives, a continuation of Laredo's historical role as a gateway between nations. 

The Birth of an Interstate: From Trail to Superhighway 

The transition from cattle trails to interstate highways was not an overnight phenomenon. It was a gradual process that mirrored the nation's shift from an agricultural to an industrial economy. As the 20th century dawned, the advent of the automobile began to reshape America's transportation needs. The old trails, many of which had evolved into rudimentary roads, were no longer sufficient for the demands of a rapidly modernizing nation. 

The Federal-Aid Highway Act of 1956 marked the birth of the modern interstate system. Proposed by President Dwight D. Eisenhower, whose experiences with inadequate road infrastructure during World War II underscored the need for a national highway network, the Act was the product of collaborative efforts from numerous key figures in Congress. 

Senator Albert Gore, Sr. of Tennessee, a prominent advocate for the Interstate Highway System, co-sponsored the Act. In the House, Representative George H. Fallon of Maryland, Chairman of the House Committee on Public Works' Subcommittee on Roads, played an important role in drafting and promoting the highway legislation. The financing mechanisms essential for the project's realization were largely shaped by Senator Harry F. Byrd of Virginia, Chairman of the Senate Finance Committee, and Representative Hale Boggs of Louisiana, a member of the House Ways and Means Committee. Notably, these committees later assumed central roles in shaping and approving international trade agreements, thereby foreshadowing the future significance of I-35 in facilitating cross-border commerce.     

This ambitious project sought to connect major urban centers, enhance national defense mobility, and facilitate interstate commerce. Notably, I-35 was an integral component of the original plan for the Interstate Highway System, unveiled in 1956. This inclusion underscores the route's strategic importance in facilitating the uninterrupted flow of people and goods across the nation, connecting the heartland from north to south. 

In planning I-35, engineers, and planners drew inspiration from the well-worn paths of cattle trails. These trails had already established numerous towns and cities along their routes, serving as a natural blueprint for the highway's construction. The concept of "path dependency," which states that past decisions and events influence future developments, is evident in the story of I-35. The highway's route was not drawn arbitrarily on a map but was instead the product of decades of economic and social development along the old trail corridors. 

The specific routing of I-35, including its southern terminus in Laredo, was influenced by a complex interplay of federal, state, and local interests. While there's no direct evidence of individual legislators advocating for I-35 to start in Laredo, the city's strategic position as a strategic point of entry between the U.S. and Mexico made it a logical choice. Texas legislators like Senator Lyndon B. Johnson, then-Senate Majority Leader, and Representatives Joe M. Kilgore and O.C. Fisher likely ensured Texas's interests were represented in the highway planning process. 

The decision to anchor I-35 in Laredo reflected both historical patterns and forward-looking economic strategies. It acknowledged Laredo's long-standing role in cross-border trade while positioning the city as a critical component in the modernizing transportation network of the United States. 

While the vision for I-35 was laid out in 1956, turning that vision into reality was a monumental task that spanned decades. Construction of I-35 began in the late 1950s and continued through the 1960s and 1970s. The complexity of the project, coupled with varying priorities and funding challenges in different states, meant that some sections were not completed until the 1990s. This extended timeline reflects not only the scale of the Interstate Highway System but also the evolving needs and challenges faced by the communities along its route. 

As sections of I-35 opened to traffic, towns that had once serviced cattle drives found themselves connected by ribbons of asphalt, their fortunes now tied to this new artery of commerce. The highway became both a physical and economic lifeline, reshaping the landscape of America's heartland and setting the stage for decades of growth and development. 

The Economic Impact: Transforming the Heartland 

As I-35 took shape, it did more than just facilitate faster travel; it fundamentally reshaped the economic landscape of America's heartland. Cities along its path experienced rapid growth and development. Dallas-Fort Worth, Austin, San Antonio, Kansas City, and Minneapolis-St. Paul all benefited from their position along this vital north-south corridor. 

The highway's impact on the Texas economy has been particularly significant. According to the Texas Department of Transportation (TxDOT), the I-35 corridor is responsible for $1.2 trillion—or 49%—of the state's GDP. This vital economic artery includes a supply chain network valued at more than $300 billion in trade and supports 1.6 million jobs associated with over 52,000 manufacturing, transportation, and warehousing establishments. 

The agricultural sector has seen profound changes due to I-35. The same regions that once sent cattle north now found new markets for a diverse array of farm products. Produce from the Rio Grande Valley could reach northern markets faster than ever, while manufactured goods from the industrial Midwest flowed south with unprecedented efficiency. 

The most significant economic impact of I-35 has been its role in facilitating international trade. The highway is the primary land route for goods moving between Mexico and Canada, earning it the nickname "NAFTA Highway." This role was solidified with the North American Free Trade Agreement (NAFTA) in 1994 and further strengthened by its successor, the United States-Mexico-Canada Agreement (USMCA), which came into effect in 2020. 

The strategic importance of I-35 extends far beyond its role as a domestic trade corridor. The highway connects Laredo not only to America's heartland but also to key trade states like Minnesota and Michigan, which play vital roles in today's North American trade landscape. This north-south artery has become increasingly critical in the era of integrated continental commerce under NAFTA and now USMCA. 

Furthermore, I-35's significance doesn't end at the U.S.-Mexico border. It connects seamlessly with Mexico's Federal Highway 85 (MX 85), which forms part of the Pan-American Highway. This extension effectively transforms I-35 into a crucial segment of a comprehensive Western Hemispheric highway system, facilitating connectivity between North America, Central America, and South America. This continental connection emphasizes I-35's multifaceted role, extending beyond U.S.-Mexico trade, to encompass commerce throughout the Americas. 

The impact of these trade agreements on I-35 traffic has been substantial in Laredo, Texas, which serves as the southern terminus of I-35. In 2023, Laredo surpassed Chicago O'Hare International Airport and the seaport of Los Angeles to become the United States' number one port of entry by total trade value, handling an astonishing $321 billion in import and export cargo. 

This extensive international trade has fostered the development of a comprehensive logistics and distribution infrastructure along the I-35 corridor. Warehouses, trucking companies, and intermodal facilities have emerged to cater to the substantial flow of goods.  

The economic impact extends beyond trade and logistics. The Texas Department of Transportation (TxDOT) estimates that I-35 supports 72 higher education institutions and nearly 400,000 jobs in the national security sector within Texas alone. This concentration of educational and high-tech jobs has led to the corridor being referred to as "Silicon Prairie" in certain regions.  

However, this economic success has also brought challenges. Nineteen of Texas's top 100 most congested roadway segments are along the I-35 corridor. To address these issues, 111 highway projects have been completed along I-35 since 2015, with a total investment of $7.1 billion. 

As I-35 continues to evolve, its role as an economic artery for the heartland of America remains more crucial than ever. The highway's future will likely be shaped by ongoing efforts to balance economic growth with sustainability and quality of life for the communities it serves. 

A Highway of History and Hope 

From its roots in the dusty cattle trails of the 19th century to its current status as a vital artery of international trade, Interstate 35 has served as both an observer and a catalyst for the economic and societal development of the American heartland. It stands as a testament to the enduring importance of transportation infrastructure in shaping our communities and our economy. 

As we navigate the challenges of the 21st century - from climate change to technological disruption - I-35 will undoubtedly continue to evolve. But whatever form it takes in the decades to come, this great highway will always bear the imprint of its history. In its lanes, we can still hear the echoes of cattle drives and pioneer wagons, reminding us of the indomitable spirit that built not just a road but a nation. 

The story of I-35 is, in many ways, the story of America itself - a tale of ambition, progress, and the constant push to connect and move forward. As we travel its length, from the international border at Laredo to the northern reaches of Minnesota, we're not just driving on a road. We're traveling through time, across a landscape shaped by centuries of human endeavor, on a highway that continues to write its story with every passing mile. 

Dr. Daniel Covarrubias is the Director of Texas A&M International University's A.R. Sanchez, Jr. School of Business Texas Center for Economic and Enterprise Development. 

Gerry Schwebel is the Executive Vice President of the Corporate International Division at IBC Bank-Laredo, Texas.