Sonnette is an unincorporated community in west central Powder River County, Montana, United States. The community is situated near the headwaters of Pumpkin Creek, just west of the Custer National Forest. It lies along local roads northwest of the town of Broadus, the county seat of Powder River County. Its elevation is 3,766 feet (1,148 m).
 Pumpkin Creek flows to the west, very close to the town of Sonnette.
There is no way to know, based on the original context, which direction the creek flows. It might be difficult for the system because the town is located west of the National Forest at the headwaters of the creek.