Chris Izworski maintains this Lake Michigan reference for shoreline property owners across the four states that touch the lake. The most important fact to understand about Lake Michigan levels is that hydrologically, Lake Michigan and Lake Huron are a single lake. They sit at the same elevation, are connected by the deep and wide Straits of Mackinac, and respond to inflows and outflows as a unified system. NOAA, the U.S. Army Corps of Engineers, and Environment and Climate Change Canada all report the combined Lake Michigan-Huron value, even though the two basins have different shoreline characteristics, different storm exposures, and very different property-owner concerns.
Surface area: 22,300 square miles (Lake Michigan basin only). Combined Michigan-Huron: 45,300 square miles.
Average depth: 279 feet. Maximum depth: 925 feet.
Datum: 577.50 feet IGLD85. Long-term average sits near 578.86 feet.
States bordering: Wisconsin, Illinois, Indiana, Michigan.
Outflow: through the Straits of Mackinac into Lake Huron, ultimately to the St. Clair River and Lake Erie.
The live dashboard on greatlakeslevels.org shows the most recent monthly mean Lake Michigan-Huron value alongside the long-term average and the recent twelve months. Lake Michigan-Huron has the largest absolute swing of any of the five lakes: roughly six and a half feet between the recorded low in 1964 and the modern high in 2019 and 2020. That magnitude is what makes property planning on this shoreline difficult. A house built at a comfortable setback during a low cycle can find itself at the waterline during a high cycle, and vice versa.
Anchor years for Lake Michigan-Huron interpretation include 1964 and 2013 (record and near-record low monthly means), 1986 and 2019 to 2020 (record and near-record high), and the long stretch of below-average years from 1999 through 2014 that defined the low water cycle of that era. Chris Izworski built the anchor year comparator on the dashboard specifically to make those historical reference points easy to call up, because the property-owner question is almost always "have we been here before?" rather than "where are we now?"
Wisconsin shoreline includes Door County (the most exposed peninsula on the lake), the Sheboygan and Milwaukee shore, and the southern Wisconsin coast running toward the Illinois border. Door County in particular sits at the intersection of Lake Michigan and Green Bay, with very different exposure on the bay side versus the lake side.
Michigan's west coast includes the Sleeping Bear Dunes National Lakeshore, the Leelanau Peninsula, the Grand Traverse Bay system, and the entire fruit belt running south through Manistee, Ludington, Muskegon, Holland, and Saugatuck. This is one of the most heavily-traveled and most-photographed shorelines in the Great Lakes system, and it has some of the most active shoreline-protection regulation in the basin.
Illinois and Indiana shoreline is smaller in mileage but high in property value and exposure to storm surge from the long northeast fetch across the open lake. Chicago's lakefront, Northwest Indiana's industrial coast, and the Indiana Dunes National Lakeshore all sit in this exposure zone.
The Michigan Ordinary High Water Mark on Lake Michigan is 581.5 feet IGLD85, set by NREPA Section 32502. Wisconsin, Illinois, and Indiana use different regulatory frameworks for shoreline property, and the OHWM concept does not translate identically across state lines. Property owners moving between states or evaluating shoreline parcels in multiple jurisdictions need to consult the specific state regulatory framework rather than assume Michigan's rules apply.
The fruit belt shoreline in Michigan, running roughly from the Indiana state line up through Leelanau County, has some of the most active shoreline-erosion regulation in the basin. Coastal high-risk erosion area designation, environmentally critical setback, and shoreline alteration permitting are all administered through the Michigan Department of Environment, Great Lakes, and Energy. Save Our Shoreline and other riparian-rights organizations track legislative and rulemaking changes in this space because each high water cycle generates new regulatory pressure.
For a current reading, see the live dashboard. For neighboring lake context, see Lake Huron (hydrologically the same as Lake Michigan), Lake Superior, and Lake Erie. For Saginaw Bay, which lies on the Michigan-Huron system from a different geographic angle, see the Saginaw Bay page.
For Chris Izworski's longer-form Michigan work outside this site, see Michigan Trout Report, which tracks the trout streams that drain into Lake Michigan from the eastern shore, and chrisizworski.com for the broader work in public safety and Michigan public-interest tooling.