Sylvan Lake, South Dakota
Swimming, kayaks, and the trailhead for Black Elk Peak, inside Custer State Park
Updated: July 16, 2026 | $25 per vehicle | 17 acres | Man-made, 1881
Quick Answer: What is Sylvan Lake?
Sylvan Lake is a 17-acre man-made lake at 6,145 feet, in the northwestern corner of Custer State Park at the top of the Needles Highway. Theodore Reder dammed Sunday Gulch to create it in 1881. Because it is inside the park, you need the $25 per vehicle entrance license, good for seven days. You can swim at a designated beach, rent canoes, kayaks and paddleboards first-come first-served, and fish from the pier, but no motorized craft are allowed. It is also the main trailhead for Black Elk Peak, 7 miles round trip with 1,100 feet of gain. One warning that decides your whole route: the Needles Highway tunnels are as narrow as 8 feet, so large RVs must approach on SD-89 from Custer instead. Lodging at the lake is just a lodge and a campground, so most people sleep in Custer or Hill City.
Black Elk Peak is not the highest point east of the Rockies
You will read this everywhere, on trail signs and travel blogs alike, and it is false. Black Elk Peak is 7,242 feet, which is genuinely remarkable for this part of the country, but Guadalupe Peak in Texas is higher and it too sits east of the Rocky Mountains.
The version that actually holds up, and the one South Dakota's own tourism office uses, is stranger and better: Black Elk Peak is the highest elevation between the Rocky Mountains and the Pyrenees in France. That is a claim about a very long line across the Atlantic, and it is true.
“Due to low, narrow tunnels, large RVs or vehicles towing campers should avoid Needles Highway (SD Hwy 87N) and approach the area using SD Highway 89 north from US Highway 16A in Custer.”
Table of Contents
The Lake Itself
Sylvan Lake reads as the most natural thing in the Black Hills and is in fact entirely artificial. Theodore Reder built a dam across Sunday Gulch in 1881 and the water backed up against the granite. The rock formations that make every photograph of this place work were already there. The lake simply arrived at their feet.
| Elevation | 6,145 feet |
| Size | 17 acres |
| Created | 1881, by Theodore Reder, who dammed Sunday Gulch |
| Where | Northwestern corner of Custer State Park, top of the Needles Highway |
| Entry | $25 per vehicle, valid 7 days (the Custer State Park license) |
| Motorized boats | Not permitted |
| On screen | National Treasure: Book of Secrets |
No, it is not behind Mount Rushmore
National Treasure: Book of Secrets stages its finale as though Sylvan Lake sits directly behind Mount Rushmore, and a steady trickle of visitors arrives at Rushmore each summer looking for it. It is not there. Sylvan Lake is roughly 30 minutes away, on the other side of the Needles, inside Custer State Park. The two are a comfortable pairing on the same day, but they are not the same place, and the film's geography is invented.
Getting There, and the Tunnel Problem
Sylvan Lake sits at the top of the Needles Highway (SD-87N), which is 14 miles of switchbacks, granite spires and hand-cut tunnels that took until 1922 to finish. It is part of the Peter Norbeck National Scenic Byway, it is the single best drive in the Black Hills, and you should budget 45 to 60 minutes for it at the posted 25 mph or slower. The road closes to traffic in winter.
If you are driving anything large, do not take the Needles Highway
This is the detail that ruins people's afternoons. The tunnels on the Needles Highway were cut through solid granite a century ago and they are genuinely, alarmingly narrow:
| Tunnel | Width | Height |
|---|---|---|
| Needles Eye | 8 ft 0 in | 9 ft 9 in |
| Iron Creek | 8 ft 9 in | 10 ft 10 in |
Game, Fish & Parks tells large RVs and anything towing a camper to avoid SD-87N entirely and come up SD-89 north from US-16A in Custer instead. Note what that means in practice: the scenic, obvious-looking approach from Hill City is the tunnel route, so if you are in a big vehicle, Custer is the more practical base. Measure your rig before you commit. There is nowhere to turn around once you are in the queue.
On drive times: we are not going to print them. Neither Game, Fish & Parks nor the park concessionaire publishes drive times to Sylvan Lake from the surrounding towns, and the Needles Highway routing swings them so wildly that a number without a stated route is worse than none. The one figure we can source is Mount Rushmore, about 30 minutes. Be aware too that the distances Expedia and similar sites show as "X miles from Sylvan Lake" are straight-line radius figures, which mean nothing on a mountain road with 25 mph switchbacks. For distances we can actually stand behind, see our Black Hills driving distances guide.
Swimming, Boats and Fishing
Swimming
Allowed, at a designated swim beach, and it is one of the genuine draws here. Pets are banned on the swim beaches and alcohol is not permitted in the zoned swim area. Remember the lake sits at 6,145 feet: the water is cold, and it stays cold through August. The Black Elk Peak trailhead is just across the footbridge from the beach, which is why the two get done in one day so often.
Boat rentals
Canoes (up to three people), one and two-person kayaks, and paddleboards, from the Sylvan Lake Store and also at Legion Lake Lodge. The important part: first-come, first-served, with no reservations taken, so on a hot July afternoon you queue or you miss out. Bring ID, it is required. Hours follow the lodge store. No motorized craft on the lake, ever.
Fishing
Allowed, with a fishing pier and shore access. You need a South Dakota fishing license, which is sold at Sylvan Lake Lodge. The resident and non-resident rules, and the age at which a licence starts being required, are fiddly enough that we would rather send you to the source than paraphrase them wrong: check Game, Fish & Parks before you cast.
On rental prices
We are not quoting them. The operator's own rate card is still headed "2025 Rates", which means it is either stale or simply not updated for this season, and either way we would be guessing at what you will actually be charged. Ask at the Sylvan Lake Store. Budget for it being the sort of thing you pay by the half hour.
Hikes from Sylvan Lake
This is the real reason Sylvan Lake matters. It is not just a pretty lake, it is the trailhead cluster for the best hiking in the Black Hills, and your $25 park license covers all of it. One honest note before the list: published distances and times for these trails disagree with each other, sometimes badly, including between two pages on the same official site. Where that happens we say so rather than pick a number and pretend.
Sylvan Lake Shore Trail
The one everybody does, and the reason a lot of people remember Sylvan Lake at all. A flat loop right around the water that squeezes between the granite slabs at the far end. If you have an hour and no ambition, this is the walk.
Distance: 1 mile loop
Time: About 1 hour
Difficulty: Easy to moderate
Black Elk Peak (Trail #9)
The big one. The trailhead sits at Sylvan Lake and begins just across the footbridge by the swimming beach, though most of the route is in Black Hills National Forest, inside the Black Elk Wilderness. There is a historic stone fire tower at the summit. Sources disagree on timing: South Dakota tourism says 2 to 4 hours, the park concessionaire says 4 to 5. For seven miles and 1,100 feet at this elevation, plan for the longer end.
Distance: 7 miles round trip, 1,100 feet of gain
Time: Around 4 to 5 hours
Difficulty: Difficult going up, moderate coming down
Sunday Gulch Trail
The trailhead is behind the dam, and the start is the memorable part: a steep scramble down through boulders with handrails bolted into the rock. Custer State Park Resort calls it 2.8 miles and Game, Fish & Parks calls it a 4 mile loop, which likely reflects whether the shore connector is counted. We have not been able to confirm which, so treat it as a half-day either way.
Distance: Roughly 2.8 to 4 miles, depending on the source
Time: 2 to 4 hours
Difficulty: Strenuous
Cathedral Spires
Granite fins that look like a cathedral organ, and worth the effort. Be careful reading distances for this one: the Cathedral Spires spur is quoted at 1.6 miles one way, while Trail #4A as a through-route is quoted at 7 miles round trip. Those measure two different things and get blended together constantly. The #4A trailhead is 2 miles east of Sylvan Lake on the Needles Highway, not at the lake.
Distance: See note
Time: About 2 hours
Difficulty: Strenuous
Little Devils Tower (Trail #4)
A granite summit with one of the best views in the Hills. You can start from the Sylvan Lake lot, or from the trailhead 1 mile east on SD-87, which saves you roughly half a mile of round trip. Not to be confused with Devils Tower in Wyoming, which is a different place entirely and about two hours away.
Distance: See note
Time: Half day
Difficulty: Strenuous
Which one? If you have a morning and reasonable fitness, Black Elk Peak is the one you will remember, and the stone fire tower at the top is worth the climb on its own. If you want the drama without the summit, Sunday Gulch is the most interesting terrain, and the handrail section at the start is unlike anything else in the park. If you have small children or an hour, do the shore loop and swim afterwards. More detail on all of these in our best hikes in the Black Hills guide.
Sylvan Lake Lodge and Campground
Sylvan Lake Lodge
- • Open May through October. Dining runs May to mid-October.
- • 31 cabins plus lodge rooms, with a wing added in 1991.
- • The site was chosen by Frank Lloyd Wright, which is the fact people are usually surprised by.
- • Larger units include the Senator's Cabin (sleeps 10), the Cathedral Spires Group Cabin (sleeps 20) and the Theodore Reder Cabin.
- • An electrical fire in 2021-22 damaged mostly one wing. Rooms were rebuilt and renovated in 2022 and came back online in 2023.
- • The stone and timber building dates to 1937 or 1938. We would love to be more precise, but the concessionaire's own site says both on different pages.
Sylvan Lake Campground
- • 39 sites at 6,200 feet, the highest campground in the park.
- • A quarter mile south of the lake on SD-87N.
- • Open from Open House Weekend to October 1.
- • $16 a night for a tent site with no electric, $34 with electric.
- • Book at reservations.gooutdoorssouthdakota.com or 1-800-710-2267.
- 🚨 Not suitable for large tents, or RVs over 27 feet. Combined with the tunnel limits, big rigs are effectively designed out of this end of the park.
Why you probably will not get a room at the lake
Add it up: 31 cabins and 39 campsites. That is the entire overnight capacity of one of the most visited places in South Dakota, and the lodge shuts for half the year while the campground closes on October 1. Demand is not the constraint here, supply is. Sylvan Lake Lodge does take bookings through Expedia and Hotels.com, so it is worth a look, but if you are planning inside a few months you should assume you are sleeping somewhere else and be pleasantly surprised if you are not.
Tours Near Sylvan Lake
Sylvan Lake sits at the top of the Needles Highway, so most Custer State Park tours pass through or near it. A guided trip also solves the tunnel problem if you are travelling in something large. Most of these have free cancellation through Viator.
Mt Rushmore, Crazy Horse and Custer State Park Wildlife Loop Tour
What makes this tour unique is the combination of three of Western South Dakota's most iconic destinations – Mount Rushmore, Crazy Horse Memorial, and Custer State Park Wildlife Loop – into a single, comprehensive, and fully narrated experience. Over 8-9 hours, you'll not just see these landmarks, but gain a deeper understanding and appreciation for their history, cultural significance, and natural beauty. We always give the guest time to buy their lunch during the tour.
Private Custer State Park Safari and Hiking Tour
You will have an opportunity to explore different areas within Custer State Park. The day will be spent within this historic State Park.
Icons of the West: Black Hills & Badlands 3-Day Tour
This tour covers the three major areas of the Black Hills and Badlands. You can put down the planning, and relax as we take you to the significant points of interest. At times, we may deviate from the itinerary for some surprise visits. We can spend more or less time at each location based on your interests. Our guides are trained in a way that enhances your experience on so many levels. We care about your time here most of all and are willing to go out of our way to ensure you have an excellent experience. Photography is something we love as well, and photos will be provided at the end of each day, free of charge.
Wildlife Biologist’s Guide to the Black Hills: Private Tour
This isn’t just a tour, it’s a deeply personal exploration of the natural world, guided by a professional wildlife biologist who brings every moment to life. Designed exclusively for your group, the experience is entirely private and tailored to your interests, pace, and curiosity. What sets it apart is the focus on nature in its purest form, no monuments, no crowds, just the living heartbeat of the Black Hills. You’ll explore vast prairies, winding byways, underground caves, and wildlife-rich habitats with a guide who reads the landscape like a storybook. Rather than simply pointing out animals or naming plants, your guide offers insight into the complex relationships that tie geology, ecology, and wildlife together. You’ll walk away with not only stunning photos but a meaningful connection to the land itself. Unhurried, immersive, and rich with discovery, this tour invites you to slow down, look deeper, and experience South Dakota as few ever do.
Custer State Park Wildlife Loop and Needles Highway Tour
What makes this tour unique is its immersive journey through Custer State Park's Wildlife Loop, offering a chance to witness the majestic buffalo herds, especially enchanting in springtime with the adorable newborn calves. Beyond the buffalo, you'll encounter a diverse array of wildlife, from graceful antelope and deer to playful prairie dogs and the charming begging burros, all set against the backdrop of breathtaking scenery. The 7-8 hour narrated experience provides an in-depth understanding of the park's ecosystem and its inhabitants, making it more than just a sightseeing tour, but an educational and unforgettable wildlife adventure.
Private Tour of Mount Rushmore, Crazy Horse and Custer State Park
Mount Rushmore is more than just the carvings. They have secrets that are not easily revealed. GeoFunTrek's guides are local experts with decades of experience. We have no seasonal guides, part-time guides or trainees. This is a family-owned business and all tours are conducted by family members: Cindy, Christopher and John Esposti. We have the knowledge and skills to make your day one to remember. You will always get the A-team when you tour with GeoFunTrek Tours! All tours are PRIVATE TOURS, exclusive to the group booking the tour, and no additional guests will be included. Children must be accompanied by one adult. Children 3 years and younger are free and will have their own seat. Children's car seats must be supplied by family members when required. Our vehicles are SUV's, and a larger vehicle (van) may be rented for larger groups. This is a great tour for 3-generation families with Children, multiple couples and groups of friends.
Prices and availability provided by Viator. We earn a commission on bookings, at no extra cost to you.
Where to Stay Near Sylvan Lake
With only a lodge and a campground at the water, nearly everybody visiting Sylvan Lake sleeps in a town nearby and drives in. The two obvious bases are Custer and Hill City, and for once the choice is not really about price or charm. It is about what you are driving.
- Custer: The practical choice, and the only sensible one if you are in an RV or towing, because SD-89 north out of Custer is the approach that avoids the Needles Highway tunnels altogether. Custer also puts you next to Jewel Cave and Wind Cave.
- Hill City: More central to the whole Hills and closer to Mount Rushmore, and a lovely drive in over the Needles. Just be aware that the direct approach from Hill City is the tunnel route, so this is a car-and-small-SUV base.
- Keystone: Works if Mount Rushmore is your main event and Sylvan Lake is the side trip rather than the reason you came.
- Rapid City: The widest choice of hotels and the airport, at the cost of the longest drive each way.
Sylvan Lake Lodge full, or closed for the season? Everything else in and around the park:
Still deciding on a base for the whole trip? Our where to stay in the Black Hills guide compares every town, and the Black Hills itinerary shows where a Needles Highway and Sylvan Lake day fits.
Frequently Asked Questions
Is Black Elk Peak the highest point east of the Rockies?
No. It is 7,242 feet, but Guadalupe Peak in Texas is higher and also east of the Rockies. The accurate claim, and the one South Dakota tourism uses, is that Black Elk Peak is the highest elevation between the Rocky Mountains and the Pyrenees in France.
Do you have to pay to get into Sylvan Lake?
Yes, because it is inside Custer State Park. The park entrance license is $25 per vehicle and valid for seven days. There is no separate charge for the lake, and the same license covers the Black Elk Peak, Sunday Gulch, Cathedral Spires and Little Devils Tower trailheads.
Can you swim at Sylvan Lake?
Yes, at a designated swim beach. Pets are not allowed on the swim beaches and alcohol is banned in the zoned swim area. At 6,145 feet the water stays cold well into summer.
Is Sylvan Lake natural?
No, it is man-made. Theodore Reder dammed Sunday Gulch in 1881. You will see 1891 quoted widely, including on Wikipedia, but Game, Fish & Parks and Custer State Park Resort both say 1881.
Can I take an RV to Sylvan Lake?
Not over the Needles Highway. The Needles Eye tunnel is 8 ft 0 in wide by 9 ft 9 in high and Iron Creek is 8 ft 9 in by 10 ft 10 in. Game, Fish & Parks says large RVs and vehicles towing campers should avoid SD-87N and come up SD-89 north from US-16A in Custer. The campground also turns away RVs over 27 feet.
Is this the lake from National Treasure?
Yes, Sylvan Lake appears in National Treasure: Book of Secrets, but the film's geography is fiction. The lake is about 30 minutes from Mount Rushmore, not directly behind it.
How long is the walk around Sylvan Lake?
The Sylvan Lake Shore Trail is a 1 mile loop and takes about an hour at a wander, rated easy to moderate. It is the walk to do with children or before a swim.
Planning a Sylvan Lake Day
Buy the $25 park license, drive the Needles Highway if your vehicle fits and SD-89 from Custer if it does not, get there early enough to park, and decide between the shore loop and the summit. Swim afterwards either way. Then sleep in Custer or Hill City, because there are 31 cabins at the lake and everybody wants one.