Aínsa (Aragonese: L'Aínsa) is the main town in the Aínsa-Sobrarbe municipal territory, Aragon, Spain.

It is located south of the Pyrenees, in a geologically interesting setting at the north of Huesca. Besides the surrounding mountain landscape, the 12th-century Iglesia parroquial de Santa María church and the 11th-century castle are the main sights of the town.

It is believed that there is a connection between the Ainsa and the Anza family surnames.

• Kingdom of Sobrarbe

• Spanish: Guide of Ainsa
• Aínsa Town Hall
• Villa de Aínsa
• Ainsa city guide at HitchHikers Handbook