Counties you have been to that no other Atlasian has

[muon2]

Here are some guesses for me in Minnesota, though snowguy probably has a bunch of these:

Goodhue I went to college 7 miles away and biked frequently, plus the drive through Red Wing is my favorite alternative to I 94 between Mpls and Chicago.

Dodge MN 56 to US 14 was the back way from Northfield to Rochester.

Watonwan One of my best friends from college lived one county to the west, so MN 60 through this county was the way to get there.

I can remove some from your list. My comments are in italics.

[muon2]

Probably none. The furthest downstate I've been is Springfield, and Muon's obviously been there. So unless he takes a different route than I do

I have been there many ways, just to try different scenery. Since I frequently stay in Peoria, I often pass through Stark Co., IL. Anyone been there?

Last weekend I went to the original state capital of IL, Kaskaskia, the only incorporated place in IL west of the Mississippi. It's in Randolph Co, IL, the home of Popeye. Anyone been there?

[muon2]

Still no one for Somerset, ME or Franklin, ME? Piscataquis, ME, too, but I imagine someone has been to Katahdin.

I often took weekend trips in the 80s to ME, including Somerset and Franklin.

[muon2]

No one here has any reason to go to Sheridan County Nebraska I would think.

I haven't been through there, but I have been in six NE counties further west: Dawes, Box Butte, Sioux, Scotts Bluff, Banner and Kimball. Kimball's on I-80, but I've used NE 71 and US 385 to go up to Hot Springs, SD.

[muon2]

Anyone here been to Van Wert county, Ohio? I'm pretty sure I drive through that county to visit relatives every so often.

I like US 30 as alternative route from Columbus to Chicago. So it's on my list, too.

[muon2]

No one ruled out these:

Lewis, NY
Mono, CA
Hinsdale, CO
Schuyler, NY

Here's some more tries:
Allengany, NY and others near it
Ulster, NY
Chenango, NY

Some counties near and including Clayton, IA and Crawford, WI

I've picked up Schuyler. Allegany, Chenango, Ulster and most of southern NY by travelling along I-86, the Finger Lakes, and Catskills.

I've been to counties in and around Clayton IA, traveling along both sides of the upper Mississippi.

[muon2]

Ocean, NJ
Sussex, DE
Wicomico and Worcester, MD
Accomack and Northampton, VA
Beaufort, SC

Yes to the above. I've vacationed in Rehoboth Beach, DE and Hilton Head, SC.

I've still not heard any responses to Stark or Randolph, IL.

[muon2]

Have other people been to Northeastern California?  I grew up in Nevada County, but I've been everywhere within a two county radius of there, I think.

And international doesn't count folks!  I'm sure I've been to regions of Indonesia none of y'all have been to, as well as possibly the nation of Liechtenstein. 

I actually spent part of my honeymoon in Liechtenstein.

I posted two IL counties before, that never got a hit from another poster, so since the thread is renewed I'll go again.

Stark, IL
Randolph, IL

Here's a few other other less traveled counties from the Midwest that I visited last year.

Henry, IA
Jefferson, IA
Van Buren, IA
Scotland, MO
Schuyler, MO
Adair, MO
Sullivan, MO
Grundy, MO