William O'Brien State Park

Marine on St. Croix, MN

4.6(1,321 reviews)

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About this campground

William O'Brien State Park north of Marine on St. Croix in Minnesota offers partial hookup RV and tent camping adjacent to St. Croix River. Ample outdoor activities include hiking and fishing.

What campers say

William O'Brien State Park offers varied scenery and many well-maintained trails, including an easy riverside loop plus longer hiking and biking routes and several overlooks. Canoe and kayak rentals make Lake Alice and the St. Croix accessible, though some visitors have found Lake Alice unusually low or drained. Campgrounds are convenient for RVs during off-peak stays but can feel cramped on busy weekends. Amenities include a helpful visitor center, some primitive restrooms on longer trails, and availability of an all-terrain access chair. A few guests reported ticks, strict ranger enforcement, and occasional missing trail signs, so come prepared.

Our summary of 1,321 traveler reviews.