Which river makes up a large part of the boundry between mexico and the united states

The Rio Grande

Since 1848, the Rio Grande has denoted the limit among Mexico and the United States from the twin urban communities of El Paso, Texas, and Ciudad Juárez, Chihuahua, to the Gulf of Mexico.

Explanation:

In that capacity, crossing the stream was the getaway course utilized by some Texan captives to look for opportunity.

The Río de la Plata starts at the juncture of the Uruguay and Paraná waterways at Punta Gorda and streams eastbound into the South Atlantic Ocean.