During surveys for Thamnophis gigas (Giant Gartersnake), I observed an adult T. sirtalis fitchi with unusual coloration— a yellow-cream background color with some typical red coloration laterally, but with very minimal amounts of the dark slate-black (along the sides of the yellow dorsal stripe and on top of the head) that normally predominates in this subspecies (Fig. 1; LACM [Natural History Museum of Los Angeles County] PC 2339, photo voucher). The snake was captured in a modified minnow trap on 21 May 2017, in Sutter County, Sacramento Valley, California, USA. Prior to this capture, our survey crew made two sightings of similarly marked T. s. fitchi at the same field location, and another snake with similar markings was captured at a nearby field location on 13 May 2016 (LACM PC 2341, photo voucher).