Highlights: Development of six potent diazirine-containing photoprobes based on Huwentoxin-IV. Photoprobes specifically photolabel purified bacterial-NaV1.7 VSD2 chimeric channels. Proteomic mass spectrometry identifies binding site on S1-S2 loop and S3 helix. Proposed model of HwTx-IV binding reveals importance of K27 and R29. Summary: Voltage-gated sodium (NaV) channels respond to changes in the membrane potential of excitable cells through the concerted action of four voltage-sensor domains (VSDs). Subtype NaV1.7 plays an important role in the propagation of signals in pain-sensing neurons and is a target for the clinical development of novel analgesics. Certain inhibitory cystine knot (ICK) peptides produced by venomous animals potently modulate NaV1.7; however, the molecular mechanisms underlying their selective binding and activity remain elusive. This study reports on the design of a library of photoprobes based on the potent spider toxin Huwentoxin-IV and the determination of the toxin binding interface on VSD2 of NaV1.7 through a photocrosslinking and tandem mass spectrometry approach. Our Huwentoxin-IV probes selectively crosslink to extracellular loop S1-S2 and helix S3 of VSD2 in a chimeric channel system. Our results provide a strategy that will enable mapping of sites of interaction of other ICK peptides on NaV channels.