Campgrounds that are open all year

Check out Ebenezer Park in Rock Hill, SC just south of Charlotte, NC. It is a county park on the Lake. about 70 full hookup sites with a very nice waterfront pier. Very quiet and around $25 a night.

Thanks for the ideas !!!

Shenandoah River State Park, in Bentonville, VA, near the northern corner of the state, is open for camping all year. (According to the sign, its full name is the Raymond R. "Andy" Guest, Jr. Shenandoah River State Park, or some permutation of that; it sometimes appears on maps with various shortened names.)

Promised Land State Park in PA also has some camping available all year, or very nearly all year; it's maybe 30 miles east of Scranton.

I've stayed at both a couple times during late fall and winter months. Electricity is available, and water hookups at Shenandoah River SP. I think the water was turned off at Promised Land when I was there (or maybe it was an electric-only loop), but I was using my internal tanks anyhow due to it being snowy and freezing.

A little further south, Claytor Lake SP, SW of Roanoke, VA a bit, has very easy access to and from I-81. Once you get into the Carolinas and Tennessee, a lot of parks are open year-round, as you guessed.

Depending on what you want, if you want quiet and as secluded as you can get. And are travelling I 95 try Medoc Mountain state park It's about 25 miles below the Va/NC state line a few miles off of 95.
Another favorite for us when just passing through is Santee state park on Lake Marion in SC, and this is also just off of I-95

The Jonestown/Hershey KOA just off I-81 is open all year. Others that we sometimes stop at on our January trek south are:

Shenandoah Valley Campground, Mt Jackson, VA off I-81 (not the one in Verona)

Ft Chiswell RV Park, Max Meadows, VA intersection of I-81 and I-77

Carowinds Ft Wilderness Campground, Charlotte, NC off I-77

Little Cedar Creek Campground, Ridgeway, SC off I-77

Jolly Acres RV Park, St George, SC off I-95

If you use the AllStays Camp & RV app, it has a filter for campgrounds that are open year round.