Iron ore shipments surged while limestone faltered on the U.S. Great Lakes in May, according to figures released by trade group the Lake Carriers' Association (LCA).
Iron ore shipments from U.S. Great Lakes ports climbed 8.4% compared to the same month a year ago, reaching 5.4 million tons. May loadings also came in 4.7% above the month's five-year average, a sign of strengthening demand heading into summer.
For the first five months of 2026, however, the iron ore trade has not fully recovered from an earlier-year slowdown. Year-to-date tonnage stands at 12.2 million tons, up 4.1% from the same period in 2025, but still 6.2% below the five-year average for that stretch.
Limestone told a different story. Shipments from U.S. quarries on the Great Lakes fell 8.1% in May from a year earlier, to 2.7 million tons, and came in 5.4% below the month's five-year average.
The slump in limestone has deepened through the first five months of the year. Year-to-date, U.S. Great Lakes limestone shipments total 3.9 million tons — a drop of 14.9% compared to the same period in 2025 and 15.7% below the five-year average, signaling a prolonged soft patch in demand for the construction and steelmaking aggregate.
The LCA represents the U.S.-flag carriers operating on the Great Lakes and tracks monthly commodity movements across the freshwater system.
