The North Pacific Rim is a segment of the circum-Pacific orogenic belt lying along the great circle between Mesoamerica and Indochina. Paleotectonic reconstructions rely upon integration of information about rocks exposed on land, crustal thicknesses, paleolatitudes of crustal blocks, sediment layers cored at sea, and geomagnetic anomalies. Continental margins have been modified by accretion of oceanic materials during subduction, suturing of continental blocks by collision, and opening or trapping of marginal seas. Prior to the breakup of Pangaea, a vast Paleopacific seafloor was built by spreading coeval with the subduction that elsewhere assembled Pangaea. After the breakup of Pangaea, circum-Pacific subduction accreted deformed increments of the Paleopacific seafloor to the edges of continental blocks now along the North Pacific Rim. Cretaceous crustal collisions closed the North Pacific Rim and isolated the Arctic Ocean. Paleogene accretion of the continental Okhotsk block caused subduction to shift from the Bering shelf edge to the Aleutian chain. The elbow in the Emperor-Hawaii hotspot track records a change in Pacific plate motion at about the same time. Current circum-Pacific arcs include east-facing island arcs and west-facing continental arcs in a consistent pattern that implies net westward drift of continental lithosphere with respect to underlying asthenosphere.