From October 2011 to July 31, agents apprehended more than 40,000 non-Mexican migrants, compared to about 39,000 individuals from Mexico.
The Border Patrol says non-Mexican illegal immigrants are accounting for a slender majority of the agency's apprehensions in Texas.
The number of non-Mexican migrants apprehended during the same 10-month period a year earlier was about 16,000.
Rosendo Hinojosa, Rio Grande Valley Border Patrol Sector chief, said Friday the non-Mexican migrants are coming mainly from El Salvador, Guatemala and Honduras. Hinojosa says the figures are not unheard of, as his sector traditionally has been an entry point for illegal immigrants from Central America.
Experts say rising violence as well as economic conditions in various Central American countries is probably fueling the increase.