A programmable input structure for a programmable logic circuit provides the capability of "fanning out" a selected signal to two or more input terminals of the programmable logic circuit, thereby increasing the routability of the logic block input signals. A logic block for an integrated circuit includes a programmable logic circuit and input multiplexers programmably selecting an input signal to provide to the programmable logic circuit. Also included in the integrated circuit are fan multiplexers that do not drive the programmable logic circuit directly. Instead, the fan multiplexers drive two or more of the input multiplexers that can, optionally, drive other input multiplexers in the same logic block, providing additional selection options among potential input signals. In some embodiments, the fan multiplexers are driven by global and/or regional clock signals. Thus, existing clock distribution structures can be used to provide high fanout input signals to the programmable logic circuit.