| Big River | |
| Map Size: | 300 |
| Pushpin Map: | USA Oregon |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of the mouth of the Big River in Oregon |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Oregon |
| Subdivision Type4: | County |
| Subdivision Name4: | Lane and Douglas |
| Length: | 12miles[1] |
| Source1: | Calapooya Mountains |
| Source1 Location: | Douglas County, Oregon |
| Source1 Coordinates: | 43.5403°N -122.8978°W[2] |
| Source1 Elevation: | 3288feet[3] |
| Mouth: | Coast Fork Willamette River |
| Mouth Location: | Lane County, Oregon |
| Mouth Coordinates: | 43.5953°N -123.0675°W |
| Mouth Elevation: | 1004feet |
The Big River is a tributary of the Coast Fork Willamette River, approximately 12miles long, in western Oregon in the United States. It drains an area of the Calapooya Mountains south of Eugene.[1]
It rises in northern Douglas County, northwest of Huckleberry Mountain, approximately 20miles south-southeast of Cottage Grove at 43.5404°N -122.8978°W. It flows northwest through Lane County to form the Coast Fork of the Willamette at its confluence with the Little River, about 15miles south of Cottage Grove at 43.5954°N -123.0676°W[2] [1]
Flowing northwest from the northern flanks of the Calapooya Mountains in Douglas County, Big River enters Lane County about 1miles downstream from the source. Box Canyon enters from the right at about river mile (RM) 9 or river kilometer (RK) 14. Big River receives Boulder Creek from the left, then Edwards Creek enters from the right at about RM 6 (RK 10). After receiving Bar Creek from the left and Martin Creek from the right, Big River meets Little River to form the Coast Fork Willamette River about 40miles from where the larger stream meets the Middle Fork Willamette River to form the Willamette River.[1]