Big Bend or Rainbow is an unincorporated community in Placer County, California. Big Bend is located on the South Yuba River, east-southeast of Cisco Grove. It lies at an elevation of 5738 feet (1749 m).
Big Bend was the site of a travelers' inn and grocery store on the Lincoln Highway. The historic Rainbow Lodge is nearby. Today Big Bend consists of a US Forest Service campground, a fire station, and a few vacation homes.