Longest route you’ve seen both ends of

[fillup420]

For me its US 64. I have seen the east end on the Outer Banks of NC several times, and I passed the west end coming down US 160 from Colorado last December.

[jaehak]

Probably I-70 for me. It's certainly the longest road I've clinched.

[roadman]

Longest route I've seen both ends of as a driver is I-84.  Longest route I've seen both ends of as a passenger is I-89.

[1995hoo]

I was going to say I-75. I haven't clinched it (only state in which I've travelled all of it is Florida), but I've been to both ends–the Florida end multiple times, the Michigan/Ontario end on a family vacation in 1987 that saw us visit Isle Royale and then Manitoulin, followed by the ferry to the Bruce Peninsula and on down through Ontario on the way home.

But then fillup420's post prompted me to look up the exact locations of the ends of US-64 and I realized I've been to both ends of that as well, so US-64 it is. Again, not nearly a clinch.

[MNHighwayMan]

The longest route off the top of my head that I've driven to both ends of is MN-200, all 201 miles of it. I cannot think of any longer state routes (I haven't hit both ends of either MN-1 or MN-23), and there hasn't been any US or Interstate (2di ones, I mean) routes that I've driven to both ends of.

Edit: actually, scratch MN-200. MN-65 wins at this, being 272 miles long.

[Max Rockatansky]

I-10 which also happens to be my longest route clinch as well.

[TheArkansasRoadgeek]

I-630 in Little Rock.... 

[hotdogPi]

I-88 (NY), which I have clinched.

[signalman]

I-81, which I have a complete southbound clinch of and nearly a complete northbound clinch (I'm missing about 80 miles in VA and between I-80 and I-84/380 in PA).  Thanks in part to the two three fore-mentioned Interstates, I never have a reason to use that section when traveling to/from home.

Edited to add: I forgot, I have seen both ends of a longer route.  I've seen both ends of I-10.  I don't nearly have the route clinched, but I have driven the eastern terminus and I've seen the western terminus as a passenger.  I've never driven in California.  The last time I was in CA I wasn't old enough to drive.

[sparker]

I-80.  Clinched the west end (east from terminus to Reno) countless years ago; clinched the east end in 1988 (from I-287 east to its terminus).  Did the rest in one fell swoop in the spring of 1989, west-to-east, Sacramento to NJ.  Actually, one of the best road trips I ever did; set no speed records -- did it in 4 1/2 days.

[dfilpus]

US 50. I've driven less than ten miles on the highway in both Sacramento and Ocean City.

[TheStranger]

I-80 because of several vacations to the NYC area (though I haven't been on it between Cheyenne and New Jersey).

[spooky]

I thought the answer was I-90, but I just learned that it has since been extended in Seattle beyond the western terminus that I drove in 1999.

[21stCenturyRoad]

I've seen the both ends of I-10 and I-40. I've also seen both ends of Route 66 if that counts nowadays

[hbelkins]

I've been to both ends of US 64 as well, but certainly don't have it clinched.

[Brandon]

I-70, which also happens to be my longest clinch as well.

[Mapmikey]

Notable ones where I do not have a clinch of the entire route:

I-40
US 11
US 30
US 40
US 52
US 64
US 70
US 80
US 89
US 90

[Eth]

Does it have to be signed? Because if not, I think it might be FL 93.

For fully-signed routes, I can't think of anything longer than I-16. Sadly, I took I-295 around Jacksonville last summer instead of going straight through, otherwise I'd have the obvious answer of I-10.

[PHLBOS]

I-90 in MA & WA (nowhere near clinched).

Longest route clinched: I-495 in MA.

[renegade]

I have seen both ends of US-127, but have only traveled the portion from I-75 in Michigan to I-70 in Ohio, and from its junction with US-27 in Chattanooga to the town of Signal Mountain.

[roadman65]

I-10 I have seen its east end and west ends even though I have not yet clinched it all.    Seen both terminuses of I-75 but need to clinch the interstate between I-94 and US 127 in MI as the rest of it is done.

Also I have seen both ends of I-55, but not yet clinched it, and I-65 I have also seen both ends where I did clinch it through KY and TN and parts of IN and most of AL.

Oh, yes I-85 as I have driven through Petersburg, VA plenty of times on I-95 and I drove I-65 through Montgomery, AL.

[Big John]

I-90 on separate vacations to Seattle and Boston.

[formulanone]

I-90 on separate vacations to Seattle and Boston.

Same here, but nowhere near clinching it.

I think US 27 might be the longest north-south route I've seen both ends of. I know I've driven through the "north"  end of US 101 in Olympia, but can't quite confirm if I've driven along its southern terminus.

My longest entire-route clinch is I-59, although I've driven much more continuous distance of I-95, I-75; and maybe I-40 and I-20.

[kphoger]

Cool topic!

For me, it's probably I-44 (634 miles), and second place might be US-400 (481 miles).
I've really never kept track of this stuff, though, so I might be wrong.

[ekt8750]

I-76 (East)
I-476
I-85
I-87
US 13
US130