A decade-long satellite altimeter data set is used to analyze the annual variations in the sea surface height (SSH) field northeast of the Hawaiian Islands. The annual harmonic amplitudes for the SSH and the along-island geostrophic flow are 2--4 cm and 2--4 cm s-1, respectively. Although these values are an order of magnitude smaller than the regional mesoscale eddy signals, the annual SSH signals have a robust spatial structure that can be expressed as a function of distance northeastward away from the Hawaiian Islands. The annual SSH signals are then described by using trapped annual waves and a basin-scale non-propagating signal. Using the linearized vorticity equation, we suggest that the trapped annual waves are baroclinic Rossby waves that decay from the Hawaiian Islands.