William O'Brien State Park

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Close enough to be drivable, yet far enough to feel disconnected from civilization; William O’Brien State Park is a great destination for backpackers, hikers, and paddlers to escape the stresses of the city.

Written by

Molly O'Connor


12.0 miles

Destination Distance From Downtown

30.4 miles


3 of 5 diamonds

Time To Complete

2 days

1-2 days


All Seasons

All Seasons

Dog Friendly

On Leash Only


Fees Permits


$5 daily parking permit or $25 annual state parks parking permit



Only an hour’s drive north from the Twin Cities, William O’Brien State Park offers outdoor enthusiasts 1,753 acres to explore. Including a wide range of landscapes and outdoor activities, William O’Brien is a local favorite for a weekend away from the cities.

Nestled within the St. Croix River Valley, this park’s main attractions are its large tranquil meadows and scenic river views. Formed thanks to glaciers, you can still see remnants of the most recent ice age while on your hike. The rolling prairie fields, glacial potholes, and large boulders strewn across the park are only part of the geological evidence left behind. Paddlers can see the dramatic, towering bluffs and exposed sandstone from the St. Croix.

What Makes It Great

One of the highlights of William O’Brien State Park is its 12 miles of hiking trails, all of which take you through a variety of landscapes. The most popular and scenic trail in the park is the Riverside Trail. A flat 1.6-mile loop that follows Lake Alice and the St. Croix River’s floodplain, this trail offers hikers picturesque views and serene beaches, not to mention great fishing spots for walleye, bass, and brown trout.

Upland of the river is a myriad of trails connected by interwoven loops. From the visitor center, head north and cut across the campground area. North of the cabins is the Wetland Trail, which is populated by box elder and basswood trees. There is also a small lowland bog that provides habitat for a diverse community of frogs, insects, and birds, such as grosbeaks and waxwings.

Once you pass the campground and wetland, you enter the Woodland Edge Trail. Keep an eye out for a gigantic basswood tree just off the trail. Though it is tempting to walk near it, be mindful of the thick growth of poison ivy at its base. Here, the landscape rises in elevation and transitions from lowland floodplain to mixed conifer forest. During the fall, this trail features amazing colors. The red sumac compliments the white pine, while the basswood gives the trail an orange glow. Cross under the railroad bridge to see even more fall colors, and continue upward towards the Hardwoods Hill Trail. This is usually a very quiet trail, since most visitors don’t venture this far into the park, so enjoy the tranquility and fantastic views of William O’Brien State Park.

If you want to see rolling prairies and vibrant wildflower blooms, the southwestern corridor offers this and more. Follow the Woodland Edge Trail until you reach the first of two trail exits. This is the 1.1-mile Rolling Hills Savanna loop and this trail features beautiful oak savanna and patches of wildflowers. Often a popular trail during the midsummer, this trail is also colorful during the fall season as well. The second trail exit offers the 1.4-mile Prairie Overlook Trail, which offers peaceful meadows to walk through and a small pond to sit beside. If at any time you start feeling tired, all along these trails, there are trail exits that can shorten your hike and return you back to the visitor center.

Who is Going to Love It

Go to William O’Brien State Park if you want to see some of the St. Croix River’s prime scenic views, while also getting to explore miles upon miles of forested trails. You will not be disappointed by this park’s splendor. 

Directions, Parking, & Regulations

The park office is generally open starting from 8 a.m till mid afternoon. Depending on staffing, the afternoon hours vary.

After getting your permit, there are two parking lots. One is by the visitor center, only a rock’s throw from the park entrance. The other parking lot is by the swimming beach, which is down the steep hill to the southeast. Most of the trailheads start from the visitor center, except for the scenic Riverside Trail by the swimming beach.


William O'Brien State Park

16821 Obrien Trail N
Marine on St Croix, MN, 55047
45.224791, -92.7664

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