Castelnou is a municipality in the province of Teruel, in the Aragon region of Spain. It is a small, sparsely populated settlement in this part of northeastern Spain, administered as a municipality in its own right within the province.
According to the 2004 census carried out by Spain's National Statistics Institute (INE), Castelnou had a population of 109 inhabitants. That figure reflects the municipality's character as a very small rural community, with a population numbered in the low hundreds.
Beyond its administrative status and its recorded population, the available reference material provides no further details about the municipality's history, geography, economy, or landmarks.