This article describes the present legal regime applicable to the Rio
de la Plata, the wide river shared by Argentina and Uruguay. The Plata
, which drains an extensive basin covering much of Argentina, Uruguay,
Paraguay, Bolivia and southern Brazil, is an important gateway for tr
ade with the interior of the South American continent. The article dis
cusses some of the issues surrounding the exact nature of this body of
water and the consequences and present status of the question under i
nternational law. The article traces some of the geo-political interes
ts which have historically shaped the diplomatic and legal practices o
f the riparian states, Argentina and Uruguay, up to the signing of the
1973 Treaty creating a special regime for the Rio de la Plata. This c
omprehensive agreement, the Treaty of the Rio de la Plata and its corr
esponding Maritime Boundary, lays the framework for regulating most hu
man activities taking place in the river, in addition to resolving the
thorny questions arising from the exercise of each State's respective
jurisdiction. The respective powers of the riparians are analyzed for
each of the different areas and zones into which the river is apporti
oned, as well as the attributions which may be exercised by either Sta
te in the zones of exclusive jurisdiction and in the so called common
zone. Issues such as pollution prevention, pilotage, scientific resear
ch, fishing, navigation, works and rescue operations are comprehensive
ly described. The article concludes by portraying recent developments
concerning the upgrading and modernization of the Plata's infrastructu
re for navigational purposes in the context of the regional trend towa
rd privatization and deregulation.