We report cyclotron resonance (CR), transverse magnetoresistance (MR), and Hall effect studies of a series of n-type InAs1−xNx epilayers grown on GaAs with x up to 1%. The well-resolved CR absorption lines, the classical linear MR, Shubnikov–de Haas magneto-oscillations, and negative MR revealed in our experiments provide a means of probing the effect of the N atoms on the electronic properties of this alloy system and reveal qualitative differences compared to the case of the wider gap III-N-V compounds, such as GaAs1−xNx. In GaAs1−xNx electron localization by N levels that are resonant with the extended band states of the host crystal act to degrade the electrical conductivity at small x (∼0.1%). These phenomena are significantly weaker in InAs1−xNx due to the smaller energy gap and higher energy of the N levels relative to the conduction band minimum. In InAs1−xNx the electrical conductivity retains the characteristic features of transport through extended states, with electron coherence lengths (lφ∼100 nm at 2 K) and electron mobilities (μ=6×103 cm2 V−1 s−1 at 300 K) that remain relatively large even at x=1%.