Mille Mine Bat Cave

Discover Millie Hill Bat Cave & Millie Hill Trail System

Tucked away near the Michigan-Wisconsin border on the southwestern edge of the Upper Peninsula is a hidden gem that treats patient visitors to a unique, impressive wildlife display.

The Millie Hill Mine is a wondrous place, the home of an honest-to-goodness bat cave — one of North America’s biggest collections of breeding and hibernating bat colonies. Here, visitors can potentially see hundreds of thousands of bats in a place designated as a Michigan Wildlife Viewing Area.

For those who can’t get enough of Michigan wildlife, the trip can be well worth it, and additional trails in the area provide the road to an unforgettable adventure.

Millie Hill Mineshaft Bat Cave Viewing Site
Millie Hill Bat Viewing Site | photo via Jesse Land

Getting to Know the Millie Hill “Bat Cave”

You won’t become a crime fighter if you visit this Upper Peninsula spot near Iron Mountain. But visitors to the Millie Hill Mine will see a “bat cave” full of little and big brown bats (hundreds of thousands), as the name implies.

Millie Hill is one of several caves curious Michiganders and out-of-town visitors can explore!

Millie Hill was once home to the Millie Mine, which operated from 1881 to 1936. In its heyday, about a half-million tons of iron ore were hauled from it. The nearby Chapin Pit and Cornish Pump Museum are also remnants of Iron Mountain’s formerly prosperous mining era.

In the last three decades, the Millie Hill mine is one of more than 1,000 former mines in the United States that’s been turned into a bat sanctuary. Across the nation, this has helped to protect millions of bats of about 30 different species.

The mineshaft itself is now caged off and designated as an honest-to-goodness bat cave.

Millie Hill Scenic Lookout
Millie Hill Scenic Lookout | photo via heidistros

How to Get to the Millie Hill Mine

Traveling through Iron Mountain on US-2/141, residents and visitors will see a sign sure to pique their curiosity: Bat Viewing Sight, with an arrow pointing to the right.

From downtown Iron Mountain, travelers can reach the viewing area by driving up East A Street and turning left on Park Avenue. A quick left at the Bat Viewing Sign puts travelers on the trail (appropriately named Millie Hill Bat Cave Road) toward the parking area. A sign with yellow lettering featuring a hanging bat welcomes visitors to the pavilion and viewing platform.

Millie Mine Bat Cave Sign - Iron Mountain Michigan
Mille Mine Bat Cave, Iron Mountain | photo via theoriginalsightseeingsally

This entrance to this abandoned vertical iron mine — which goes down about 400 feet — looks unassuming. It’s just a hole in the grass. But the hole is covered with a steel grate that allows bats to come and go for mating and hibernation. It also prevents visitors from falling in.

The bat viewing site is just uphill from the parking lot, which offers an incredible view of bats during certain times of the year.

Visitors can enjoy a self-guided interpretive program that extolls the benefits of bats. Visitors can also learn about what types of bats live in Michigan and why bats hibernate.

Nine different species of bats live in Michigan, and according to the Michigan Department of Natural Resources, they don’t suck blood, only eat insects, are not blind, and do not get into hair.

The best times for viewing bats are in April/May and September/October at dusk. Those who arrive at the right time might see a massive display of bats in flight.

Millie Hill Scenic Lookout
Millie Hill Scenic Lookout | photo via katykat2112

A Unique Perspective on the Millie Hill Bat Viewing Site

Upper Peninsula resident Jesse Land is the former owner of the website Things to Do in the UP and shares a unique perspective of his experiences at the Millie Hill Bat Cave.

The Millie Hill Bat Cave is one of the prime attractions in the Iron Mountain area. But most people don’t what I’m about to tell you, so they miss out on the bat-viewing action.

Passing cars often brake as they pass the “Bat Viewing Area” sign in town. Many of them don’t stop, but it’s enough to get their attention.

“Huh? Bats? What?” they likely mutter as they drive on.

And on my frequent summer evening walks up the Millie Hill Trail, I’ll often encounter a group of people perched on the bat-viewing benches. I usually try to sneak past unnoticed as they stare longingly at the cage surrounding the entrance to the old Millie Mine.

And then…

This is the entrance to the “bat cave.” Batman eat your heart out.

“Hey! When do the bats come out?” they’ll inquire.

“You can see them in April and September,” I’ll say, which always begets disappointed groans.

“Really?” someone will ask.

“Yeah,” I say, as I go into unofficial park ranger mode.

“They hibernate down there from around September to April every year. So spring and fall are the best time to see them.” (For the record, it does say this on one of the nearby signs.) “Thanks,” they’ll say, not really meaning it.

I could tell them about the great view that lies just a little up the trail. Or I could encourage them to come back in September when the place is buzzing with bats. I’ve tried these things, but it’s no use, they’re officially bummed.

Sometimes I play dumb and say I don’t know when the bats come out. But then I feel bad because the poor people just keep sitting there, waiting.

And hey, if I stared at a metal cage for an hour hoping to see a bunch of bats, only to have those hopes crushed by some random guy with a camera, I’d be bummed too. I get it.

So, lesson learned here, right folks? The last few warm days of September or the first few warm days of April will usually get you a piece of the bat-viewing action, but that’s it. They bug out in summer and they’re down there sleeping in the winter.

Cool? Cool.

Bottom Line: The Millie Hill Bat Viewing Site is worth a stop, you just need to time your visit following the bats’ migration patterns. (Usually April or September.)

Scenic Overlook From Millie Hill Trail System In Iron Mountain
Millie Hill scenic overlook | photo via Jesse Land

An Iron Mountain Hidden Gem: The Millie Hill Trailhead

After (hopefully) catching at least a glimpse of bats at the Millie Hill Mine, visitors can continue through the woods and explore along the Millie Hill Trailhead.

The trail system is a multi-use trail project with nine different trails for mountain biking, walking, hiking, and biking in and around downtown Iron Mountain. With names like Knotty by Nature, Berm City, and Millie Vanillie, those who seek adventure have no shortage of options.

From the Millie Mine parking lot area, travelers can choose the easy Knotty by Nature trail or the moderate, winding Millie Vanillie trail.

Millie Hill Scenic Lookout
Millie Hill Scenic Lookout | photo via heidistros

Jesse Land, who frequently hikes around Iron Mountain, shared his thoughts on the Millie Vanillie trail:

My wife and I live near this trail and hike it often. It’s a short hike, and it’s also right in the middle of town which makes this trail an easily accessible gem.

We typically walk from the east side of town up to the trailhead off Park Street, through the towering pine trees to the scenic lookout, then down to the other trailhead across from Hardees and back. I’d recommend starting at the Park Street trailhead, though there’s also an unofficial trail that angles up Millie Hill from the Mountain View Ice Arena parking lot and connects with the main trail.

That walk (with our daughter in the stroller) takes us about a half-hour. And if you take a stroller I’d recommend jogging strollers only. My wife tried to use our regular stroller on the Millie Hill trail a few times and came back cursing. (Too much loose gravel for the smaller wheels.)

If you park at the Park Street trailhead and walk straight to the lookout it’s only a few hundred yards and can be done in less than five minutes. That’s the quickie version.

But if you walk the whole trail, take in the scenery, and read the interpretive signs you could spend an hour or so here. And in my opinion, it’s well worth it.

Millie Hill Scenic Lookout
Millie Hill Scenic Lookout | photo via heidistros

Journey to Iron Mountain to See Bats at the Millie Hill Mine

It may not have all the high-tech gadgetry of Batman’s secret headquarters, but the Millie Hill mine near Iron Mountain is nonetheless impressive. After all, not every day can you visit a real bat cave filled with hundreds of bats in the Upper Peninsula.

This hidden gem is worth a trip to Iron Mountain. With some planning and careful timing, visitors may be present to see a magnificent display of bats in flight. Experiences like these are a reminder of the many wildlife encounters visitors can have in Michigan and the stunning beauty of the Upper Peninsula.