Castro Valnera

{{Infobox mountain

| name = Castru Valnera

| photo = Castro Valnera desde el Bernacho.jpg

| photo_caption = Castru Valnera peak in 2017

| elevation_m = 1,718

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| location = Cantabria, Spain

| range = Montes de Lunada

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Castru Valnera{{cite book|last=Penny|first=Ralph|title=El habla Pasiega: Ensayo de Dialectología Montañesa|year=1969|publisher=Tamesis Books Limited|isbn=978-0-900411-05-2|pages=204|edition=1st|language=Spanish|chapter=5/1|quote=§204 San Roque de Riomiera: "[…] Montañas: Bernachu, el Castru Valnera, Cubulruyu, […]"}} (Cantabrian) or Castro Valnera (Spanish) is a peak located in the central area of the Cantabrian Mountains, in Burgos, northern Spain. It is around it that the whole Pas valley revolves, and also the source of the Miera River, between the Portillo de Lunada and Estacas de Trueba passes.

Castru in Cantabrian refers to an abrupt rocky peak.