Argo Mill & Tunnel Tour — Idaho Springs, Colorado

Discover the Argo Mill & Tunnel Tour in Colorado

Step inside one of Colorado’s most iconic mining landmarks at the Argo Mill & Tunnel in Idaho Springs. Once the longest mining tunnel in the world, the Argo transported ore from multiple mountain mines to its massive processing mill, where gold, silver, and other minerals were extracted.
Why it’s special:
The Argo complex is a National Historic Landmark and one of the best-preserved gold mills in the West—featuring original machinery, ore carts, tunnels, milling equipment, and real gold panning.

History/Story of the Argo Mill & Tunnel

Construction of the Argo Tunnel began in 1890 and took 17 years to complete. Stretching more than 4.16 miles through the mountains, the tunnel connected to dozens of mines, allowing ore and water drainage to reach the Argo Mill efficiently. At its peak, the mill processed over 300 tons of ore per day. After a major flooding event in 1943, operations ceased, but the structure survived and became a museum celebrating Colorado’s mining legacy.

What You’ll See & Do at the Argo Mill & Tunnel

• Walk through portions of the historic Argo Tunnel entrance

• See towering gold-processing machinery used for crushing and separating ore

• Watch demonstrations of original stamp mills, sluices, and gravity separators

• Explore the multi-story Argo Mill with preserved gears, belts, and ore bins

• Learn how the tunnel drained mines and transported ore by rail cars

• Pan for real gold at outdoor sluice stations—keep what you find!

• View mining artifacts, geological displays, and historic photographs

Hands-On Elements: Gold panning, ore identification displays, mill equipment demonstrations.
Photo/Video Policy: Photography allowed throughout most areas; no drones on property.
Souvenirs & Extras: Gold vials, ore samples, gems, gold panning kits, shirts, hats, toys, books.

Pricing of the Argo Mill & Tunnel Tour

• Adult Tour: $25

• Kids (ages 5–16): $15

• Children 4 & under: Free

• Gold Panning (included with tour)

• Group & school tours: Custom pricing

Practical Info for Visiting the Argo Mill

Duration: 60–75 minutes
Format: Guided tour + gold panning
Schedule & Seasonality: Open year-round; more tours during summer
Working Hours: Typically 10:00 AM–5:00 PM
Audience: Families, history lovers, geology fans, adventurers
Accessibility: Mill has many stairs; not wheelchair accessible
Safety & Restrictions:

• Closed-toe shoes recommended

• Uneven floors and steps throughout the mill

• Kids must stay with an adult
  Languages: English
  Group Visits: Excellent for schools, STEM programs, scouting groups
  What to Bring/Wear: Layers (mill can be cool), sturdy shoes
  Facilities: Gift shop, restrooms, parking, outdoor seating
  Closures & Downtime: May close during severe winter weather

Nearby

• Phoenix Gold Mine

• Idaho Springs Hot Springs

• St. Mary’s Glacier

• Historic Downtown Idaho Springs restaurants & shops

FAQs About Visiting the Argo Mill & Tunnel

Do we walk deep into the Argo Tunnel?
You’ll visit the tunnel portal and entrance, but for safety reasons the deep tunnel is closed to the public.

Is gold panning included in the tour?
Yes—every admission includes a gold panning session, and you keep whatever you find.

How old is the Argo Mill?
The mill was completed in 1910 and is one of the best-preserved gold-processing plants in the country.

Is the tour good for kids?
Yes—children love the gold panning and big machinery, though the mill’s stairs require supervision.

Can I bring pets?
Pets are not allowed inside the mill or tunnel areas.