Las montañas vs. La sierra

Question

I understand that la sierra is a mountain range and that la montaña is just one mountain. However, could you say las montañas instead of la sierra and it still mean the same thing? If not, what exactly is the difference between the two then?

Answer 1

Las montañas and la sierra can both be used to refer to a mountainous region, but a mountain range is more commonly called la sierra. Around here, the mountain range is The Andes and people frequently refer to it as la sierra. The mountainous rain forest regions are also called la sierra, but not las montañas.

Answer 2

You can use both

En las montañas de Guerrero.

En la sierra de Guerrero.

Answer 3

I'm pretty sure it's just like it is in English. "The Sierras" are a range of mountains, whereas "the mountains" refer to mountains in general.

So, you could be talking about The Sierras and refer to them as "the mountains" and be perfectly understood. But, the person you are talking to should know that you are talking about The Sierras so they won't just imagine any old mountain and possibly be confused. I would imagine that people who live very near The Sierras refer to them as "the mountains" all the time and everyone understands that. But if someone in Asia were to mention "the mountains" in casual conversation, they should not expect their listener to understand that they are talking about The Sierras.