You’re driving through East Central South Dakota, and it’s mostly corn, soybeans, and that relentless prairie wind. Then, suddenly, this massive inland sea appears out of nowhere. Honestly, if you didn’t know better, you’d think you took a wrong turn and hit the coast.
That’s Lake Thompson Recreation Area SD.
Most people think South Dakota is just the Badlands or Wall Drug, but this corner of the state is something else entirely. It’s the largest natural lake in South Dakota. Well, "natural" is a bit of a tricky word here. Back in the early 80s, this area was basically just a marshy pasture. Then the rains came and never really stopped. By 1986, the water had swallowed up roughly 18,000 acres of farmland. It’s a literal sunken world.
The Weird History of a "New" Old Lake
You’ve got to appreciate the irony. This place was made famous by Laura Ingalls Wilder—the Little House on the Prairie author. She lived in nearby De Smet, and back then, she described this area as "Dry Woods Lake."
For decades, it lived up to that name. It was dry. People grazed cattle on it. Farmers planted crops in the lake bed.
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Then the climate shifted. In the mid-1980s, a cycle of heavy precipitation turned a series of shallow sloughs into a massive, 20-foot-deep body of water. It didn't just grow; it exploded. It ate roads, drowned trees, and forced the state to completely rethink what to do with all that water.
What resulted is the Lake Thompson Recreation Area SD we see today—a premier destination for anglers and campers who want to feel like they’re in the middle of nowhere without actually being stranded.
Fishing: Why the Pros Keep it Quiet
If you talk to a local at the bait shop in Lake Preston, they might be a little tight-lipped. That’s because the fishing here is ridiculous.
Because the lake was formed by flooding fertile farmland, the bottom is a buffet for fish. All those submerged fence lines and old road beds? Those are walleye gold mines.
- Walleye: This is the big draw. They grow fast here because of the nutrient-rich water.
- Northern Pike: They’re aggressive and everywhere. If you’re casting near the weed lines, hold onto your rod.
- Yellow Perch: Great for kids and even better for a shore lunch.
- Black Bullhead and Sunfish: Plentiful enough to keep the bobbers bobbing all afternoon.
There are over 44 miles of shoreline to explore. You can launch from the boat ramp at the southern end of the recreation area, but plenty of people just pull up a lawn chair on the rocks and do just fine.
Camping at Lake Thompson Recreation Area SD
Kinda surprisingly, the campground is actually quite modern for being in such a rural spot. You aren’t exactly roughing it unless you want to.
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There are 103 campsites, and almost all of them have electricity. If you’re bringing a massive 40-foot RV, you’re good—there aren't any weird size restrictions. However, I’ll be honest with you: shade is at a premium. Since the lake is relatively young and the area is wide-open prairie, the trees haven't all reached "majestic canopy" status yet. If you’re visiting in July, bring an awning or a screen house. You’ll need it.
For those who hate sleeping on the ground, they have five camping cabins. They’re basic—think beds and a roof—but they have heating and AC. That AC is a lifesaver when the South Dakota humidity kicks in.
If you have a huge group, there’s a five-bedroom lodge. It used to be a farmhouse. Now, it’s basically a lakeside mansion you can rent for family reunions. It’s got a full kitchen, which beats cooking hot dogs over a smoky fire for three days straight.
Trails and the Great Outdoors
The hiking here isn't going to win any "most vertical gain" awards. It’s flat.
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But the Prairie View Trail is a solid 1-mile loop that gives you a real feel for the "sea of grass" that the early settlers talked about. You’ll see sanderlings, snow geese, and if you’re lucky, maybe a rare white-winged scoter. It’s a birdwatcher’s paradise because the lake sits right in the middle of a major migratory flyway.
Quick Facilities Breakdown:
- Water Sports: Kayaking and jet skiing are huge here. The lake is big enough that you aren't constantly bumping into other boats.
- Swimming: There’s a designated beach area. It’s sandy-ish and protected from the main boat traffic.
- Winter: People don't stop coming when the snow hits. The ice fishing is legendary. Just make sure you have a 4x4 or a snowmobile if the drifts get high.
What Most People Miss
The mistake people make is staying only at the park.
You’re less than 10 miles from De Smet. Even if you aren't a fan of the books, the Ingalls Homestead is a fascinating look at how people survived this landscape before we had GPS and climate-controlled RVs.
Also, watch the weather. Seriously. The wind on Lake Thompson can go from a breeze to a gale in twenty minutes. If you see dark clouds over the horizon, get off the water. The fetch on a lake this size means the waves can get surprisingly high, surprisingly fast.
Logistics and Small Details
The park is open year-round, which is great, but the "modern" amenities like flush toilets and showers usually shut down from October 1st through April 30th. You’ll be relying on vault toilets (the fancy name for outhouses) during the winter months.
Entrance will cost you about $8 for a daily vehicle pass. If you're planning on hitting more than one South Dakota state park, just buy the annual pass for $36. It pays for itself by your fifth visit.
Actionable Tips for Your Trip
- Book Early: The lodge and cabins fill up months in advance, especially for holiday weekends.
- Bug Spray is Non-Negotiable: Between the water and the tall grass, the mosquitoes can be fierce. Don't buy the "natural" stuff; get the DEET.
- Check the Water Levels: While the lake is huge, South Dakota is prone to droughts. It’s always smart to check the latest SD Game, Fish & Parks reports before you haul a deep-draft boat out there.
- Download Offline Maps: Cell service is... okay... but it can get spotty once you're deep into the recreation area. The "Go Outdoors SD" app lets you download park maps for offline use.
Pack a cooler, check your tire pressure, and get out there. The prairie is waiting.