Simpson Creek is a long second-order tributary to the Niobrara River in Keya Paha County, Nebraska.
Simpson Creek rises on the Oak Creek divide about north-northeast of School No. 69 in Keya Paha County and then flows southeast to join the Niobrara River about southeast of School No. 69.
Simpson Creek drains of area, receives about of precipitation, and is about 6.25% forested.