Great Lakes stone runs about six weeks ahead of the Census spending data, which makes it one of the better leading indicators for Midwest paving and concrete work. July was good.
U.S.-flag limestone shipments from U.S. ports reached 3,134,730 net tons, up 8.7 percent from July 2025’s 2,882,554 and 3.2 percent above the five-year July average of 3,036,667. It’s the strongest July since 2023, when the trade moved 3,388,330 tons.
The Year Is Still Negative
Year to date through July, shipments total 10,094,538 net tons — down 3 percent against 2025’s 10,402,975 and 4.2 percent below the five-year average of 10,537,782. So July didn’t fix the year. It closed some of the gap that a weak spring opened, which is roughly what you’d expect from a paving season that started late and then ran hard.
Stone moves out of Calcite, Cedarville, Drummond Island, Port Inland and Presque Isle in Michigan, and Marblehead in Ohio. The Lake Carriers’ Association puts total annual U.S.-flag Great Lakes cargo above 90 million tons across iron ore, stone, coal, cement and other dry bulk.
The Denominator Changed and Nobody Announced It
Here’s the part estimators need to know. The report carries a one-line note: as of April 2026, Canadian ports are no longer supplying limestone shipment information.
That breaks the series. The 2026 total of 3,134,730 tons is U.S.-only. The 2025 comparison figure of 3,528,972 includes Canadian volume. Any coverage reporting a decline in “Great Lakes limestone trade” by putting those two numbers side by side is comparing different things, and the apparent drop is a reporting artifact rather than a demand signal.
From here forward, every Great Lakes stone headline is structurally understated against its own history. Anyone using this series to forecast aggregate availability or price should rebase to U.S.-only and stop reaching back past March.
What It Signals for Q4
A positive July against a still-negative year is a reasonable read for Midwest highway and site work heading into the fall. It’s also consistent with what the broader materials data has been saying: volumes recovering, margins not. Midwest industrial work is absorbing some of it, including the Gary Works blast furnace reline in northwest Indiana. Aggregate producers spent the summer shipping more rock for less money per ton, and a strong stone month doesn’t by itself change that.
The comparison worth making is against the five-year averages rather than against last year. July beat its five-year average by 3.2 percent while the year to date sits 4.2 percent below its own. That gap says the season compressed rather than expanded, which matters for anyone scheduling crews and plants around a fall paving push. A compressed season means the same tonnage moving through fewer weeks, and that shows up as haul capacity and plant throughput constraints rather than as a supply shortage.
The Lake Carriers’ Association publishes the report as data only, with no attributed comment.