How to use this page
Marine doesn’t have a river gauge of its own, so this page uses the two nearest ones. St. Croix Falls (about 15 river miles upstream) has a flow record going back to 1903 and is the best indicator of how fast the water past Marine is moving. Stillwater (about 12 miles downstream) is the gauge the National Weather Service uses for flood warnings on the lower river.
- For paddling and fishing, watch the St. Croix Falls flow and its comparison with normal. “Normal” means the middle half of all flows ever measured on today’s date.
- For flooding, watch the Stillwater stage. The NWS calls 80 feet “action stage” and 87 feet “flood stage.” In big snowmelt years the river spreads into low ground along its banks, closing floodplain trails and landings.
- For safety, remember that the numbers lag: heavy rain upstream in Wisconsin can raise the river at Marine for days afterward.
Live numbers refresh in your browser when you open the page. Charts and long-term statistics update every time the site is rebuilt. Readings are provisional data from the U.S. Geological Survey and NOAA and may be revised.
Why the St. Croix is special
The St. Croix drains a mostly forested watershed in northwest Wisconsin and east-central Minnesota, which is why it runs clearer than the Mississippi it joins at Prescott. In 1968 it was among the first rivers protected under the national Wild and Scenic Rivers Act, and today the National Park Service manages more than 200 miles of it and its tributary the Namekagon as the St. Croix National Scenic Riverway.
Last reviewed October 1, 2026.
