Longest signed county roads

[thspfc]

There is a continuious CTH-F in Wisconsin that runs for a ridiculous 62 miles in three different counties (Lafayette, Iowa, and Dane), from near Belmont to Black Earth. It takes a very indirect way, passing through Darlington, Blanchardville, and Blue Mounds. Other county roads that are numbered/lettered the same but are really long and in multiple counties?

[Max Rockatansky]

J16 in California is the longest here at 75.74 miles. 

[formulanone]

I asked a similar question many moons ago:
https://www.aaroads.com/forum/index.php?topic=10577

I think San Bernardino CR 66 is the longest in the US, at 175 miles. It's the old alignment of US 66.

But yeah, some of those Wisconsin county routes seem to go on for some distance.

[Max Rockatansky]

I asked a similar question many moons ago:
https://www.aaroads.com/forum/index.php?topic=10577

I think San Bernardino CR 66 is the longest in the US, at 175 miles. It's the old alignment of US 66.

But yeah, some of those Wisconsin county routes seem to go on for some distance.

In regards to Old US 66 I believe the County Route is bisected by the Marine Corps Base in Barstow.  Also, I've never sign any County Route signs east of Barstow until Ludlow either.  There also isn't any official definition of what San Berndarino County Route 66 entails mileage wise apparently:

https://www.cahighways.org/CR-66.html

[GaryV]

In Michigan F-97 runs for about 72 miles, including a few miles concurrency with M-18.

Solo, H-58 runs 68 miles in and around Pictured Rocks.

[TheHighwayMan3561]

MN:
Cook 12 (55 miles, MN 61 at Grand Marais to Saganaga Lake)
Lake 2 (50 miles, MN 61 at Two Harbors to MN 1 at Isabella)
St. Louis 7 (50 miles, US 53 at Twig to US 169 at Mt. Iron)
St. Louis 4 (65 miles, MN 194 at Duluth to MN 135 at Biwabik)
Pine/Carlton 61 (~70 miles after the gaps are accounted for)

[NWI_Irish96]

Indiana has only three signed county roads. Clark County decided to sign its decommissioned state roads under the same route numbers.
County 160 is 8.5 miles long
County 403 is 5.5 miles long
County 311 is 2.2 miles long

[TheGrassGuy]

CR 519 in NJ passes through 3 counties and is 88.54 mi long

CR 527 in NJ passes through 6 counties (!) and is 84.86 mi long

[ftballfan]

In Michigan, CR 669 runs from the Manistee/Lake county line to Lake Michigan in Leelanau County, a distance of 61 miles: https://www.google.com/maps/dir/44.1659607,-85.9816679/44.9383924,-85.872713/@44.9232557,-85.8637534,13.58z/data=!4m2!4m1!3e0?hl=en

It includes a two-mile concurrency with M-55 in Manistee County, a short concurrency with US-31 in Benzie County, and a one-mile concurrency with M-72 in Leelanau County.