Little Si is a mountain in the US state of Washington, named after its taller neighbor, Mount Si. It has an elevation of 1,576 feet. and lies on the western margin of the Cascade Range just east of the town of North Bend. Little and Big Si were named after local homesteader Josiah "Uncle Si" Merritt. Little Si is a distinct mountain peak from Mount Si, with a different trailhead and a valley that separates the two peaks. The Little Si trailhead is at approximately 47°29′14″N 121°45′12″W.