Castellanos is a Spanish habitational surname with the meaning "(from a place founded or inhabited by) Castilians". Notable people with the surname include:\n\nAnswer this question based on the passage: where does the last name castellanos originate from?
Please answer the following question by reasoning step-by-step.
Spanish
The relevant information is: Castellanos is a Spanish habitational surname with the meaning "(from a place founded or inhabited by) Castilians".

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Therefore, the answer is Spanish