Correlation of monthly inter-regional river flow and composite analysis of large-scale climatic patterns associated with high and low monthly regional river flow are presented for the northern North Atlantic domain for 1968--1997. Hydrological regions are defined using cluster analysis. Adjacent hydrological regions generally display year-round positive correlation of river flow. For the first time, inverse river flow relationships are identified between North America and Europe in autumn, and between northern and southern regions of northern Europe from April--May and July--December. Composite analysis shows linkages between northern European river flow and the Icelandic Low, Azores High and intervening pressure gradient. River flow in northeastern North America is more closely associated with the East Coast pressure trough. Trans-Atlantic hydrological teleconnections appear related to the North Atlantic Oscillation, with the inverse meridional relationship in northern Europe linked, in part, to the Scandinavian teleconnection pattern.