DELVALLE or DEL VALLE, Aristbbolo (delval'yay), Argentine statesman, born in Buenos Ayres in 1847. He was graduated at the University of his native City, and began practice at the bar in 1869. He identified himself with the national autonomist party, was soon acknowledged as one of its leaders, and elected in 1874 senator for the province of Buenos Ayres. He was reelected for several terms, and distinguished himself as an orator and defender of the autonomy of the provinces against encroachments of the Federal power. In 1875 his party nominated him for governor of the province, but he was defeated. During the dispute between Chili and the Argentine Republic concerning their boundary in Patagonia, he, together with the U. S. minister, endeavored to bring about a pacific solution of the question, and their efforts were rewarded by the boundary treaty signed in Buenos Ayres, 23 October 1881. In 1884 he was again one of three persons proposed by his party for the nomination for governor; but D'Amico was considered a stronger candidate, and was elected. Delvalle continues one of the most influential members of the Federal senate. He has published "introduction al dereeho administrativo" (Buenos Ayres).