GUALEGUAYCHU, a town and river port of the Province of Entre Rios, Argentina, on the river of the same name, II m. above its confluence with the Uruguay and about 13o m. N.W. of Buenos Aires. Pop. (1925) 21,622, the tributary territory having inhabitants. It is the centre of an important cattle-raising country, and meat is chilled and beef extract manufactured in the town. There are also tanneries and shoe factories. Gualeguaychu is on a branch of the Entre Rios railway, and is also served by river steamers.