What contributed most to rapid westward expansion after the Mississippi in the late 19th c.?

Steamboats were essential for transportation on rivers and were instrumental in early commerce and travel. However, their reach was limited primarily to navigable waterways, which restricted movement to specific routes. While they played a role in transportation, they did not match the overall impact of railroads on facilitating extensive land travel and economic growth across vast distances.

Canals were crucial in the early 19th century for transporting goods between regions, particularly before the widespread adoption of railroads. They significantly reduced transportation costs and time compared to overland routes. Yet, by the late 19th century, the rapid development of railroads overshadowed canals, as trains could cover greater distances much faster and more efficiently than canal systems.

Turnpikes were private roads that charged tolls for usage, improving overland travel in the early 19th century. However, their capacity to handle large volumes of freight and passenger traffic was limited compared to railroads. As railroads expanded, the significance of turnpikes diminished, making them less relevant to the rapid expansion that characterized the late 19th century.