Semur-en-Vallon

{{Infobox French commune

|name = Semur-en-Vallon

|commune status = Commune

|image = Ecoles communales de Semur en Vallon.jpg

|caption = The school of Semur-en-Vallon

|arrondissement = Mamers

|canton = Saint-Calais

|INSEE = 72333

|postal code = 72390

|mayor = Yvan Bosnyak{{cite web|title=Répertoire national des élus: les maires|url=https://www.data.gouv.fr/fr/datasets/r/2876a346-d50c-4911-934e-19ee07b0e503|website=data.gouv.fr, Plateforme ouverte des données publiques françaises|date=2 December 2020|language=fr}}

|term = 2020–2026

|intercommunality = Vallées de la Braye et de l'Anille

|coordinates = {{coord|48.0239|0.6544|format=dms|display=inline,title}}

|elevation min m = 104

|elevation max m = 184

|area km2 = 15.13

|population = {{France metadata Wikidata|population_total}}

|population date = {{France metadata Wikidata|population_as_of}}

|population footnotes = {{France metadata Wikidata|population_footnotes}}

|demonym = Semurois, Semuroise

|website =

}}

Semur-en-Vallon is a commune in the Sarthe department in the region of Pays de la Loire in north-western France.