Big Cliff Dam, Gravity dam in Marion County and Linn County, Oregon.

Big Cliff Dam is a concrete gravity dam on the North Santiam River, spanning the Linn County–Marion County border in the Oregon Cascades. It stands 2.7 miles (4.3 km) downstream of Detroit Dam at river mile 47 and was built between March 1949 and May 1953 alongside it. Its reservoir, Big Cliff Lake, rises and falls by up to 24 feet (7.3 m) daily as the dam re-regulates Detroit's power releases.

The dam was completed in 1953 as part of a major water management project for the Willamette Valley. Its construction represented a significant infrastructure development for the region's power and water needs.

The dam created a lake that serves as a recreation destination for both locals and visitors, while supporting irrigation for farming in the area. The water body has become part of daily life for surrounding communities and contributes to the region's economic foundation.

The site is easily accessible with good viewpoints where visitors can take in views of the structure and reservoir. The best time to visit is during dry months when walking paths and viewing areas are most easily navigable.

The structure uses specialized techniques to manage water temperature in ways that protect native fish species and improve their survival conditions. This aspect of water management often goes unnoticed, even though it has major ecological effects on the river ecosystem.