what 3 countries does mexico border?
United States of America
entailment
 In Mexico , topographical officer George W. Hughes reported to Secretary of State John M. Clayton that a railroad across the isthmus was a “ feasible and practical ” idea . Clayton then instructed Robert P. Letcher , the minister to Mexico , to negotiate a treaty to protect Hargous ' rights . The United States ' proposal gave Mexicans a 20 % discount on shipping , guaranteed Mexican rights in the zone , allowed the United States to send in military if necessary , and gave the United States most @-@ favored @-@ nation status for Mexican cargo fees . This treaty , however , was never finalized . 

entailment
 = = = Western Mexico to El Salvador = = = 

entailment
 = = = Nicaragua , Guatemala , and southern Mexico = = = 

entailment
 = = = Spain , Mexico , and the Republic of Texas = = = 

entailment
 = = = Texas to Nicaragua = = = 
