Apparatuses, methods, and systems are disclosed for interlace determination. One apparatus includes a processor that determines a system bandwidth including multiple interlaces. Each interlace of the multiple interlaces includes a set of physical resource blocks (“PRBs”) that are uniformly spaced in frequency. The processor also determines a first set of interlaces of the multiple interlaces for a first device. The first set of interlaces includes one or more interlaces. The apparatus includes a transmitter that transmits a first signal to the first device. The first signal indicates the first set of interlaces, and a number of bits of the first signal is less than a number of interlaces of the multiple interlaces.