A three-dimensional primitive-equation model is employed to investigate how an initially eastward jet responds to isobaths that diverge eastward. This problem is investigated using first a barotropic model and then a baroclinic model. In the barotropic regime, the diverging isobaths force an initially supercritical jet to widen and become subcritical after a hydraulic jump. Increasing eastward advection of vorticity moves the diverging point eastward and narrows the jet locally but widens the jet farther downstream. The incoming jet axis is fixed at a preferred latitude due to the steep meridional bottom slope upstream. In the baroclinic regime, the eastward divergence of the jet becomes much more pronounced. This strong divergence leads to the bifurcation of the jet downstream. The northern branch flows northeastward and the main branch continues eastward. The former is a western boundary current along the northeastward continental slope. The bifurcation of baroclinic jets is caused by hydraulic jumps reinforced by instabilities of the baroclinic current system. Among possible applications, the model is particularly relevant to the bifurcation of the Gulf Stream to the south of the Grand Banks, where the essentially zonal isobaths begin to bifurcate eastward.