Thunder Hole

At a glance

• Location: Park Loop Road on Mount Desert Island
• Elevation: About 40 feet
• Best timing: 1 to 2 hours before high tide offers the best chance of hearing the boom.
• Facilities: Parking, restrooms, a shuttle stop, and a store
• Amenities: Snacks, gifts, souvenirs, books, exhibits, and interpretive information
• Access: Wheelchair-accessible upper viewing deck
• Good for: Children, coastal views, photography, and passport stamps
• Open: Acadia National Park is open year-round.

Why visit

Thunder Hole is a narrow inlet carved into Mount Desert Island’s rocky eastern shore. Incoming waves compress air within the channel, producing a powerful sound resembling thunder.

The effect depends on tides and waves, so the inlet does not always roar. Under favorable conditions, spray can rise above 40 feet. The site remains a popular year-round stop.

Getting there

Thunder Hole is on Park Loop Road, just under 2 miles from Sand Beach. The parking lot and gift shop entrance is on the road’s right side.

Thunder Hole Parking is at the site. Ocean Drive Parking is about 0.2 miles away, and Gorham Mountain Parking is about 0.3 miles away. Fabbri Picnic Area Parking is about 0.5 miles away.

The fare-free Island Explorer serves Thunder Hole at regular intervals during the day. Its stop is near the parking lot entrance. Wait along the path on the road’s left side.

Visitors can also reach Thunder Hole on Ocean Path. Hulls Cove Visitor Center is about 7 miles away.

Nearby gateway communities include Bar Harbor, about 5 miles away, and Southwest Harbor, about 7 miles away. Ellsworth is about 19 miles away. These are straight-line distances, not driving distances.

Air travel options include Bar Harbor Airport (BHB) and Bangor International Airport (BGR).

What to see and do

Start at the upper viewing area for broad coastline views and interpretive displays. This level also serves as a scenic viewpoint and photo spot.

Stone stairways descend toward a lower deck beside the water. Metal handrails line the stairs. At low tide, visitors can descend for a closer view of cliff walls shaped by repeated wave action.

The best chance of hearing the signature boom is generally 1 to 2 hours before high tide. Storms and changing tides can push water into the channel, forcing trapped air outward with a loud reverberation.

A store at the site sells snacks, gifts, souvenirs, and books. Thunder Hole also has a passport stamp location, restrooms, parking, and a shuttle stop.

History and nature

Thunder Hole demonstrates how water has shaped Acadia’s coastline over long periods. Waves repeatedly entering the inlet carved the channel and adjacent cliff walls.

When water surges into the confined space, air escapes under pressure. The resulting reverberation gives Thunder Hole its name. Spray has been observed rising more than 40 feet.

The surrounding granite ledges and outcrops can be exposed to sudden waves. Even when conditions appear calm, an unexpected wave can wash across the rocks.

When to go

Thunder Hole is visited throughout the year. For the sound effect, arrive 1 to 2 hours before high tide. Conditions still vary with waves, weather, and the changing tide.

Summer temperatures in Acadia range from 45°F to the listed seasonal maximum. Fall ranges from 30°F to the listed seasonal maximum, with first frost typically arriving in mid-October.

Snowfall usually begins in November and may continue through April. Average accumulation is 73 inches. Winter temperatures range from 14–35°F, while spring starts around 30°F.

Winter moisture can make the lower stairs and deck especially slippery. During storms, the park may close parts of the walkway for safety.

Accessibility

A wheelchair-accessible upper viewing deck sits just off a path from Park Loop Road. It provides coastline views and interpretive waysides.

The stone stairs and lower decks are not accessible. They descend toward the water and may be wet or slippery.

The main parking lot contains 4 angled accessible spaces. Of these, 2 are in front of the gift shop and 2 are downhill near the restroom.

Another 2 accessible spaces are beside the road running parallel to the lot. They are just before the Island Explorer stop.

The fare-free Island Explorer provides another way to reach the site. The bus uses a marked stop near the parking lot entrance throughout the day.

Fees and rules

Acadia’s entrance fee is $35 for a private vehicle, $30 for a motorcycle, or $20 per person. The listed timed-entry reservation fee is $6.

The park is open year-round. Facility hours may differ, including those at Hulls Cove Visitor Center. Check the park’s National Park Service website before visiting.

Stay alert near the water, especially outside established walkways. Spray can rise above 40 feet, and unexpected waves can cross nearby granite ledges.

Use the handrails on the lower stairs. Wet conditions make the stairs and deck slippery, particularly during winter. Obey closures when storms affect the walkway.

Nearby trails and places

Ocean Path begins at Thunder Hole and is about 2.2 miles as mapped by the National Park Service. It provides a walking approach to the site.

Cadillac Cliffs Path is about 0.2 miles away and about 0.3 miles as mapped. Gorham Mountain Trail is also about 0.2 miles away and about 1.6 miles as mapped.

Otter Cove Trail is about 0.3 miles away and about 0.5 miles as mapped. Great Head Trail is about 0.7 miles away and about 1.7 miles as mapped.

Boulder Beach, Gorham Mountain, and Fabbri Picnic Area are each about 0.5 miles away. The Fabbri Picnic Area shuttle stop is about 0.6 miles away.

Before you go

Check current conditions, tides, weather, closures, and park alerts on Acadia’s National Park Service website. Review the park’s storm-safety information before exploring near the water.

Carry water and pack layers for changing coastal conditions. Follow posted rules, remain aware of waves, and leave no trace. Never assume calm weather makes exposed rocks safe.

Use the Island Explorer when practical. If driving, note the accessible spaces in the lot and beside Park Loop Road. Check current facility hours before relying on the store or visitor center.

Questions