Hill Annex Mine State Park

🏆🏆🏆🏆🏆 Minnesota — Walk through a massive open-pit iron mine that once powered America’s steel industry — Hill Annex operated from 1913-1978 and produced 63 million tons of iron ore! Today, paleontologists discover Cretaceous-era marine fossils (sharks, clams, nautiloids) in the 500-foot-deep pit.

Visitor Information

About Hill Annex Mine

Hill Annex Mine State Park near Calumet preserves a massive open-pit iron ore mine on Minnesota’s Mesabi Range — the richest iron ore deposit ever discovered. The mine operated from 1913 to 1978, producing over 63 million tons of iron ore. The exposed rock layers are a geological time capsule — Cretaceous-age fossils (including a mosasaur) have been found in the overburden.

Things to Do

Guided mine tours (seasonal — descend into the open pit), fossil hunting programs (real Cretaceous fossils), viewing the massive mining equipment, boat tours of the flooded pit lake, and learning about the Iron Range’s pivotal role in American industrial history.

Getting There

Located on Highway 169 in Calumet, Itasca County — on Minnesota’s Iron Range. Tours descend into the massive open-pit mine (June-September). The Mesabi Iron Range produced 75% of America’s iron ore during both World Wars — the steel that built the American military machine. The mine pit has filled with water and now hosts a unique fishery. Combine with the Minnesota Discovery Center in Chisholm for a complete Iron Range experience.

Plan Your Visit

Mine pit tours run June through September — descend into the massive open-pit mine by bus. The fossil hunting program lets visitors search for 500-million-year-old Cretaceous marine fossils in the mine walls. Fishing in the flooded pit produces surprising catches. The Minnesota Discovery Center (Chisholm, 15 miles) provides comprehensive Iron Range history. Hibbing (10 miles) is the birthplace of Bob Dylan (born Robert Zimmerman, 1941). Tour reservations recommended.

Insider Tips

Iron Range heritage: Hill Annex is a former open-pit iron mine on Minnesota’s Mesabi Range — the richest iron ore deposit in the world. Pro tip: The mine produced 63 million tons of iron ore from 1913-1978. WWII connection: Minnesota’s iron mines produced the steel that built America — during WWII, the Mesabi Range supplied 75% of the iron ore used in the American war effort. Without Minnesota iron, the tanks, ships, and planes of WWII couldn’t have been built.

Best Time to Visit

Summer: Mine tours operate June-August. July: Fossil hunts in the mine pit — Cretaceous marine fossils. Fall: Iron Range foliage. Winter: Site closed but Iron Range heritage sites are year-round.

Frequently Asked Questions

What fossils are found in an iron mine?

Hill Annex contains Cretaceous-era fossils (90+ million years old) — when a shallow sea covered Minnesota. Fossils include clams, ammonites, shark teeth, and marine reptile bones. Summer fossil hunts let visitors dig for specimens — a unique experience in a former iron mine.