Geophysical and petrologic data are presented on the northern extent of the Reykjanes Ridge. As it nears Iceland the crest of the Reykjanes Ridge is a small belt of rough topography superimposed on an elevated plateau. The rough topography consists of a series of an echelon ridges. Immediately to the southwest of the Reykjanes Peninsula the ridges strike about N35¿E and apparently represent a rotational adjustment toward the N40¿E trends on Iceland. To the south the en echelon ridges strike about N25¿E. Magnetic profiles place the peak of the magnetic anomaly either directly below or along the eastern side of the topographic highs. Eight distinctive en echelon volcanic systems (swarms) are identified and are structurally and petrologically indistinguishable from those of the western Reykjanes Ridge. Petrologically, three rock types (picrite basalts, olivine tholeiites, and tholeiites) were recovered. These form distinctive groups which match those described from the western Reykjanes Peninsula.