If you're travelling by first-class (Pullman) bus you'll arrive at the private terminal of whichever company you're travelling with - there are about a dozen in total, virtually all of them in Zona 1, including all services from the Mexican border and Petén. If you've come by second-class "chicken bus" from Antigua , you'll arrive in Zona 1 at the junction of 18 Calle, between 4 and 5 Avenidas. The Zona 4 terminal is where second-class buses to the western highlands, the Pacific coast and some towns in the eastern highlands arrive and depart; the main terminal for San Salvador is very close by on 3 Avenida and 1 Calle.