| Lost Creek | |
| Map Size: | 300 |
| Pushpin Map: | USA Oregon |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of the mouth of Lost Creek in Oregon |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Oregon |
| Subdivision Type4: | County |
| Subdivision Name4: | Lane |
| Length: | 3miles |
| Source1: | Cascade Range |
| Source1 Location: | A spring near Foley Ridge, Willamette National Forest |
| Source1 Coordinates: | 44.1608°N -122.0183°W[1] |
| Mouth: | McKenzie River |
| Mouth Location: | near Belknap Springs |
| Mouth Coordinates: | 44.1892°N -122.0658°W |
Lost Creek is an unusual 30NaN0 tributary of the McKenzie River in Lane County, in the U.S. state of Oregon. It is the lower section of a hydrogeological system, a losing stream, that begins at the base of Collier Glacier in the Cascade Range. This lower section rises from a spring complex north of Oregon Route 242 (McKenzie Highway) in the Cascade Range and flows generally northwest to meet the river near Belknap Springs. This is near the intersection of Route 242 with Oregon Route 126 and about 74miles upstream of the McKenzie's confluence with the Willamette River.[2]
Lost Creek was thus named because, if its main tributary, White Branch, is included in the reckoning, it is a disappearing stream for some of its course. White Branch flows on the surface at its headwaters then disappears before re-emerging about 9miles further downstream.[3] [4] After resurfacing, it enters Lost Creek from the left slightly downstream of the source spring.[2]
An article in The Ore Bin, a publication of the Oregon Department of Geology and Mineral Industries, explains that White Branch begins at Collier Glacier and follows a glacial trough filled with porous lava. For much of the year, a long stretch of White Branch is dry on the surface. Some of the water percolating through the lava emerges at the spring complex at the head of Lost Creek. Other water in White Branch enters the main stem as a surface tributary. The total length of the Lost Creek – White Branch system is about 20miles, of which Lost Creek forms about 3miles.[3]
Limberlost Campground, managed by the United States Forest Service, is along Lost Creek about a mile upstream of the mouth. Generally open from early May to late September, the campground has campsites, toilets, picnic tables, and fire rings but no drinking water or firewood.[5]