The Portage Lake public beach near Munith, Michigan is the day-use swim beach in the Portage Lake unit of Waterloo Recreation Area, on Big Portage Lake in northeast Jackson County. It has a beach house, a public boat launch and a 136-site modern state campground, and you need a Michigan Recreation Passport on your vehicle to drive in. The other family swimming spot in the neighborhood is the sand beach on the spring-fed swim lake at The Oaks Campground, nine minutes away, which added an Aquaglide floating water park in 2026.
Here’s how the two compare, which Portage Lake you’re actually looking for, and what else there is to do on the water nearby.
Where is the Portage Lake public beach?
Waterloo Recreation Area is the largest state park in Michigan’s Lower Peninsula at more than 20,000 acres, with 11 inland lakes. Its Portage Lake unit sits off Seymour Road between Munith and Grass Lake, and it’s the park’s main public swim spot. The DNR lists two designated swimming areas in Waterloo: this one in the Portage Lake day-use area, and a second at Sugarloaf Lake that is reserved for Sugarloaf campers. Big Portage Lake is an all-sports lake, so you’ll share the water with ski boats and fishing boats launching from the public ramp next door, and the beach gets busy on hot weekends.
The Portage Lake Modern Campground (136 sites, plus a camper cabin) is right there if you want to camp on the lake itself. Our guide to Portage Lake campgrounds compares the options in more detail.
Which Portage Lake? Michigan has several
If you searched “Portage Lake near me” and the results look confusing, that’s because the name is common:
- Big Portage Lake, Jackson County: the Waterloo Recreation Area lake in this article, next to The Oaks. There’s a smaller Little Portage Lake in Waterloo too.
- Portage Lake, Manistee County: a lake connected to Lake Michigan at Onekama, in the northwest Lower Peninsula.
- Portage Lake, Keweenaw Peninsula: the waterway between Houghton and Hancock in the Upper Peninsula.
Searches for “beaches in Portage” usually mean the city of Portage next to Kalamazoo, which is a different place about an hour and a half west of here.
Swimming at The Oaks: a sand beach on a spring-fed lake
The swim lake at The Oaks is fed by a natural artesian spring, which keeps the water clear and cool. Before the 2026 season our team rebuilt the whole beach: the weeds were treated and are now managed on a schedule, and hundreds of tons of new sand were brought in and run out into the lake, so you walk onto sand when you step in instead of mud. A campground employee called it “a huge undertaking,” but the result is a beach built for sandcastles. There are campground-provided lounge chairs (arrive early for the best ones) and a picnic lawn on the east side of the lake for cooler lunches.
Some practical notes:
- The beach is open 9 AM to 9 PM or sunset. Children under 13 need an adult with them, and there is no lifeguard.
- Non-campers can buy beach day passes at the store on weekends and holiday weekends. Visitors register at the store.
- Dogs aren’t allowed on the beach or in the swim area, but they can swim in the fishing lake, which sits downstream of the swim lake. Around the campground dogs stay leashed, with off-leash room on the back trails and in the dog run.
- The lakefront RV sites are a short walk from the sand and look straight out at the water park.
The Aquaglide floating water park
The Aquaglide is an inflatable obstacle course anchored off the beach, new for 2026. Wristbands come from the camp store, life jackets are required, it’s for ages 7 and up with a parent present for anyone under 16, and a monitor (not a lifeguard) checks wristbands and keeps everyone to the rules. In its first season it ran Thursday through Sunday plus holiday Mondays, with Thursday free for campers and a small day-pass fee on weekends; the schedule and prices for next season are on The Oaks rates page. On many 2026 weekends, hundreds of people were out on it, and our team expects use to grow as word gets around.
Part of the fun is the audience. Families on the beach and the lakefront sites have been known to hold up scorecards for dives and belly flops off the big pieces, “like it’s the Olympics of water park fun,” as one employee put it.
Other beaches and swimming spots in Waterloo Recreation Area
- Sugarloaf Lake: a 164-site modern campground with its own beach, for registered campers only.
- Green Lake: a 25-site rustic campground on a lake with a public boat launch; there’s no designated swim beach.
- Gerald E. Eddy Discovery Center (17030 Bush Road, Chelsea): the park’s visitor center, with geology and habitat exhibits and trailheads, a good rainy-afternoon stop.
Waterloo also has roughly 50 miles of hiking trails, about 20 miles of horse trails and the DTE Energy Foundation mountain bike trail. Camping next to it means your beach day can turn into a trail day without moving the camper.
Swimming campgrounds near Portage Lake
If a beach is the deciding factor, there are three campgrounds within a few minutes of each other that have one:
| Campground | Swimming | Sites | Good to know |
|---|---|---|---|
| Portage Lake Modern Campground (Waterloo) | Public beach on Big Portage Lake | 136 modern sites, 1 camper cabin | On an all-sports lake with a boat launch; Recreation Passport required |
| Sugarloaf Lake Modern Campground (Waterloo) | Campers-only beach | 164 modern sites, tiny house | Quieter swim area; no public boat traffic at the beach |
| The Oaks Campground | Private sand beach on a spring-fed lake, Aquaglide water park | About 200 RV sites (water/electric, 50 amp on short-term sites) and 20 tent sites | Fishing lake, 120 acres of trails, weekend events, camp store with scooped ice cream |
The state campgrounds are the lower-cost way to sleep next to the lake. Public parks are funded and priced differently (camping fees, the Recreation Passport and public capital investment) and offer fewer on-site amenities, while a private park like The Oaks pays for its beach, water park, Kangaroo Jumper, trails, bathhouses, staff and utilities through the site rate. RV sites start around the high $40s a night and vary by date and site. Our team’s advice: come to The Oaks if you want to stay put all weekend, and camp at Waterloo if you mainly want a place to sleep between trail and lake days.
Boating and fishing on Portage Lake
Big Portage Lake allows water skiing, jet skis and fishing, and the public launch is about nine minutes from The Oaks’ gate. Quite a few of The Oaks’ seasonal campers keep boats, and the campground stores them for free in a boat storage area, so a seasonal site plus a Portage Lake boat is a common setup. After a day on the water, Portage Lake Parlor on Seymour Road in Grass Lake is the local favorite for smoked barbecue; our team swears by the onion rings, “the kind where the batter stays on the onion ring.”
For fishing without a boat, The Oaks’ own fishing lake has a dock where kids catch bluegill and bass, and the store sells bait and gear. See our Portage Lake fishing guide for more.
Kids’ water fun beyond the beach
When the kids have had enough sun, The Oaks’ Kangaroo Jumper, a big bounce pillow added in October 2026, is free for campers and sits by the pavilion, playground, basketball court and sand volleyball. In mid-August the park runs a “summer fun” splash afternoon by the basketball court with sprinklers, water balloons and bubbles, and the camp store scoops ice cream all season. Check the events calendar for dates.
Portage Lake beach FAQ
Is there a lifeguard at the Portage Lake public beach or The Oaks?
The Oaks has no lifeguard. The Aquaglide has a monitor, guests under 16 need a parent present on the water park, and the beach rules ask for an adult with children under 13. Michigan state park beaches are generally unguarded too, so plan to watch your swimmers.
Can non-campers swim at The Oaks?
Yes, on weekends and holiday weekends with a day pass from the store. Rates are on the rates page.
How far is The Oaks from Ann Arbor and Jackson?
Munith is northeast of Jackson and west of Ann Arbor, right beside Waterloo Recreation Area. See camping near Jackson and camping near Ann Arbor.
When is the beach least crowded?
Weekdays, and the shoulder months. The Oaks is open May 1 to October 20, and May before Memorial Day, the weekend after Memorial Day, the weekends around Labor Day and October are the quietest and lowest-priced times to camp.
