Winchester is a city in Lewis County, Idaho, United States. The population was 308 at the 2000 census.
The city was named in 1900 during a meeting to establish a school district. While considering the possibilities, an individual looked at the stack of Winchester rifles stacked at the door and suggested the name, which was approved. A half mile (1 km) outside of town is Winchester Lake State Park, established in 1969. Originally it was a mill pond, created in 1910 by damming Lapwai Creek. The sawmill closed in 1963 after the mature timber in the area had been cut.
Winchester is located at 46°14′27″N 116°37′24″W / 46.24083°N 116.62333°W / 46.24083; -116.62333 (46.240935, -116.623396), in the northwestern part of the Camas Prairie, its highest elevation. Within the boundaries of the Nez Perce Indian Reservation, it lies at an altitude of 3,980 feet (1,213 m).