I believe that a barrio would be a smaller section of a town or city within its main residential section. A rancho pertaining to a town may be outside the main town or city. The rancho may be inside city limits, but usually it is outside the main residential areas of the town.

A cousin of mine owns a small rancho inside a barrio of a town so that is also possible. The town grew and built around his small rancho. On one side of the river is the main town. As you pass over the river you can see his rancho immediately to the left. just past his rancho, there was another rancho that bacame a barrio as they divided it up into lots and built up that whole area. So my cousins rancho is its own ranch, and surrounded by the residential areas of the town. His rancho is considered to be part of the newer barrio. It is relatively newer. When I was a kid it was already a small barrio that people made fun of and still called it a ranch. Sixty years later, it is a large residential section with