Campground near I-29 in MN, SD, NE or IA

There is an exceptionally nice county campground just off I29 at the Salix exit south of Sioux City. It sits on an old oxbow of the Missouri River.
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What would you consider unique?? Most that I've been in have a road or two or more, grassy, gravelly or paved sites, with or without picnic tables and hookups and with or without an office store, laundry facility, pool, stream, lake or ocean and kiddie equipment. Unique to me were the few equestrian cgs I've been to. Maybe a two level cg? Are you looking for cg uniqueness or an interesting area? Maybe a bit of definition to what you would find unique would help get you more answers?

Look up Pipestone National Monument in Mn.

Yes, we made a very pleasant afternoon stop there, but did not stay overnight. Very interesting history.

Look up Pipestone National Monument in Mn.

I 29 does not go into Minnesota but rather hugs the border nothing unique on our side.

Maybe too far off your route, but we enjoyed staying at Country Campground in Detroit Lakes, MN.

We also stayed at Indian Cave State Park in NE.