Great Lakes Limestone Trade: August Shipments Rise 1.7%

A Great Lakes bulk carrier loads limestone at a working lake-port terminal. Visual reference: Lake Carriers' Association. By Salini Krishnan U.S. limestone shipments on the Great Lakes rose 1.7% in August from a year earlier, according to the Lake Carriers' Association, but monthly and year-to-date volumes remained below their recent averages. Shipments from U.S. ports totaled 3,004,877 net tons in August, compared with 2,953,714 tons in August 2025. The August 2026 total was still 1.5% below the 2021-2025 average of 3,050,443 tons, the association said. Through August, U.S. Great Lakes limestone shipments reached 13,099,415 net tons, down 1.9% from the same period in 2025 and 3.6% below the 2021-2025 average of 13,588,225 tons. The figures show a modest year-over-year recovery in August, while also pointing to a softer cumulative pace for the shipping season. August volumes improve but remain below average The August increase represents a gain of 51,163 net tons from the same month last year, based on figures reported by the Lake Carriers' Association. However, shipments were 45,566 tons below the five-year August average. August 2026 shipments also remained below the levels recorded in 2022 and 2023, when U.S. ports handled 3,109,744 tons and 3,266,057 tons, respectively. The association's historical data show that August shipments declined to 2,902,900 tons in 2024 before rising to 2,953,714 tons in 2025 and 3,004,877 tons this year. Limestone stockpiles and conveyor equipment form part of the bulk-handling system at a Great Lakes terminal. U.S. limestone shipments in August Year U.S. ports, net tons 2021 3,019,800 2022 3,109,744 2023 3,266,057 2024 2,902,900 2025 2,953,714 2026 3,004,877 2021-2025 average 3,050,443 Source: Lake Carriers' Association. The year-to-date data present a weaker picture than the August result alone. U.S. ports handled 13,099,415 net tons of limestone through August, compared with 13,356,689 tons during the same period in 2025. The 2026 total was also 488,810 tons below the 2021-2025 average. Year-to-date shipments have declined from the recent high of 13,810,106 tons recorded in 2022. The association reported 13,617,066 tons in 2023 and 13,648,481 tons in 2024 before the total fell to 13,356,689 tons in 2025. The 2026 figure is the lowest in the association's 2021-2026 U.S. port series. U.S. limestone shipments through August Year U.S. ports, net tons 2021 13,508,781 2022 13,810,106 2023 13,617,066 2024 13,648,481 2025 13,356,689 2026 13,099,415 2021-2025 average 13,588,225 Source: Lake Carriers' Association. Why Great Lakes limestone movements matter Limestone is moved through a logistics network that links lake ports, stockpiles, conveyors and bulk carriers with industrial customers. The Lake Carriers' Association identifies stone and cement among the dry-bulk cargoes handled by the U.S.-flag Great Lakes fleet. The association says the fleet can move more than 90 million tons of cargo annually, including iron ore, stone, coal, cement, grain, salt and sand. Those materials support the broader supply chain for American industry, infrastructure and power. The supplied release does not break out the final destination or end use of the limestone shipments. It does, however, place the trade within a wider Great Lakes transportation system that also handles materials associated with construction, cement production, steelmaking and infrastructure activity. For operators and logistics managers, the shipment figures provide a measure of cargo moving through the region's bulk-materials network. For downstream users, the data offer a limited but useful view of the pace at which stone is being transported from U.S. lake ports during the shipping season. Bulk carrier loading infrastructure and limestone piles at a Great Lakes port. Canadian data create a comparison limit The 2026 figures in the supplied table cover U.S. ports only. The Lake Carriers' Association said Canadian ports stopped providing limestone shipment information as of April 2026. The U.S. ports included in the association's series are: Calcite, Michigan Cedarville, Michigan Drummond Island, Michigan Marblehead, Ohio Port Inland, Michigan Presque Isle, Michigan The historical Canadian series includes Bruce Mines, Manitoulin Island, Port Colborne and Smelter Bay, all in Ontario. Because Canadian data are unavailable for 2026, the current figures cannot be compared directly with prior years' combined U.S.-Canadian totals. The year-over-year and average comparisons in this report refer to the U.S. port series supplied by the association. That distinction is important when evaluating the broader Great Lakes limestone trade. A decline or increase in the U.S. series does not, by itself, describe total activity across both countries. What to watch next The next data points will help determine whether August's increase represents a sustained improvement or a temporary change in the monthly pattern. September navigation and cargo movement: The next report will show whether U.S. limestone shipments maintain the August pace as the shipping season continues. The supplied release does not provide a forecast for September. The gap to the five-year average: August shipments were below the recent average, while year-to-date volumes were further below it. A narrowing gap would indicate improved cumulative performance; a widening gap would point to continued weakness relative to the recent norm. Infrastructure-related demand: Limestone movements should be viewed alongside activity in the broader dry-bulk network serving industry and infrastructure. The association's release does not provide customer-level demand figures, so shipment totals should not be treated as a direct measure of construction or steel output. Data coverage: Canadian reporting remains a key limitation. Until Canadian ports resume providing information, U.S. figures will remain the most complete current measure available from the association but will not represent combined Great Lakes shipments. The Lake Carriers' Association has represented the U.S.-flag Great Lakes fleet since 1880. Its fleet transports bulk cargoes that the association describes as foundational to American industry, infrastructure and power. For additional industry coverage, visit Skillings Mining Intelligence. The association's supplied release and cargo data are available through its Great Lakes cargo reports. LinkedIn/X snippet: U.S. Great Lakes limestone shipments rose 1.7% year over year in August, but remained below the five-year average, while year-to-date volumes fell 1.9% from 2025, according to the Lake Carriers' Association.