MARTOS, a town of Spain, province of Jaen, stands on the slope of a steep hill, which is surmounted by a ruined castle, 16 miles W.S.W. of Jaen. The streets are steep, narrow, crooked, and unpaved; but there are some handsome public buildings, including several churches, chapels, and convents, town-house, prison, hospital, theatre, and orphan asylum. It is a place of resort on account of its mineral waters; and it has two bathing establishments. Pop. about 10,000.