Saint Croix National Scenic Riverway protects 406 km (252 mi) of the Saint Croix and Namekagon rivers, in Minnesota (Chisago, Pine and Washington counties) and Wisconsin (Bayfield, Burnett, Douglas, Pierce, Polk, Saint Croix, Sawyer and Washburn counties).
| Established | October 2, 1968, with the upper 160 km (100 mi) of the Saint Croix and the whole 160 km (100 mi) of the Namekagon |
| Added in 1972 | the lower 84 km (52 mi) of the Saint Croix |
| Area | about 27,304 hectares (67,470 acres) of river and forest |
| Known for | scenic, geologic, recreational, cultural and ecological resources |
| Features | the two rivers and their tributaries; rapids and waterfalls; riverside wetlands and broad floodplains; and steep bedrock cliffs |
This page is part of the National Park Service's Geodiversity Atlas, a product of the Geologic Resources Inventory. Geodiversity means the whole range of a park's geologic and soil resources and processes — rocks, minerals, sediments, fossils, landforms and the processes that shape them — and the atlas supports education, geoconservation, and management that treats the living and non-living parts of an ecosystem together.
The rocks
Most of the bedrock is Paleozoic sedimentary rock — Cambrian sandstones and Ordovician carbonates. The area's history runs through three chapters:
| Chapter | What it left |
|---|---|
| Mesoproterozoic Midcontinent Rift — the crust stretched on a regional scale | some of the oldest bedrock, in the north along the Saint Croix: lithic sandstone, mudstone and conglomerate of the Oronto and Bayfield groups |
| Paleozoic seas | the younger sandstones and carbonates |
| Pleistocene glaciation | some of the youngest units: the Miller Creek, New Ulm, West Campus, Trade River, Cromwell and Copper Falls formations, plus floodplain alluvium and colluvium |
The riverway belongs to the Superior Upland physiographic province and shares its geologic history and some of its formations with a region much larger than the park.
Maps, reports and data
The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks, and many products are still in progress:
| Product | What it is |
|---|---|
| Scoping summaries | records of meetings where park staff and local geologists set the mapping plan and the report's contents |
| Digital geologic maps | GIS files, a user guide and supporting map information; newer ones add Google Earth data and online map services |
| Reports | the park's setting and significance, notable features and processes, management issues, and geologic history, built on the maps |
| Posters | a PDF view of the GIS data; newer ones add aerial imagery or shaded relief. Included with the reports |
| Projects | the basics of the program and every product for a park |
- The riverway's products are listed in the NPS DataStore.
- A Soil Resources Inventory for the riverway is complete and also in the DataStore.
More: geologic time · explore regional geology · NPS geology
Sources
Based on "NPS Geodiversity Atlas—Saint Croix National Scenic Riverway, Wisconsin and Minnesota," National Park Service; a work of the United States government in the public domain. The atlas page's two photographs, captioned for Saint Croix Island, and its links to Saint Croix Island's home page and the Maine Geological Survey belong to a different park — Saint Croix Island in Maine — and are left out.
In these publicationsSaint Croix National Scenic Riverway
Licence: CC0 1.0 (public domain) · Adapted from www.nps.gov
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