The municipality is composed of 16 parishes, and is located in the district of Santarém.

It was founded as head-quarters of the Knights Templar in Portugal in the 12th century and contains some of the most significant Templar monuments in Europe. Tomar was especially important in the 15th century when it was a centre of Portuguese overseas expansion under Henry the Navigator, the Grand Master of the Order of Christ, successor organization to the Templars in Portugal.