States in which you have been on an Interstate/US but not state highway

[NWI_Irish96]

A state qualifies if you have traveled on at least one Interstate, Auxiliary Interstate, US, or Auxiliary US highway in the state but no signed state highways.  Remember that some states mutliplex state highways with Interstate and US highways. (If I've missed a multiplex with the routes I've listed, please let me know.)

My list:
Arkansas - Driven on I-30, I-40 and I-55 but no state highways
Delaware - Driven on I-295 but no state highways
Idaho - Driven on US 39 but no state highways
Montana - Driven on I-90, I-94, US 89 and US 212 but no state highways
Nebraska - Driven on I-76 and I-80 but no state highways
New York - Driven on I-95 and US 1/9 but no state highways
Oklahoma - Driven on I-35, I-40 and I-44 but no state highways

[hotdogPi]

None for me. I've been on at least one state route in MA, NH, ME (although I don't remember it), VT, CT, NY, NJ, PA, VA, GA, FL, AZ, and CA. No Interstates or US routes in NM or IL. DC would qualify, except it isn't a state.

[Max Rockatansky]

None for me, I've always been more of a back roads person...48 States.   

[1995hoo]

Idaho–Have not driven at all, only ridden in cabs or a friend's rental vehicle, but anyway, I have 1.02 miles of Interstate, 6.21 miles of US highways, and various local roads in the Boise area that do not seem to be signed as state highways (at least per Travel Mapping).

Wyoming–Drove from Denver to Laramie for a football trip in 2007 via US-287 in both directions. I have 28.9 miles of US highways, 3.36 miles of Business Interstate, and various local streets in Laramie that do not seem to be signed as state highways (at least per Travel Mapping).

Not sure about Mississippi.

[CNGL-Leudimin]

Bending a bit the thread title to any subdivision where I have been on a nationally-numbered road but not a regional one, for me this is true for the French region of Provence-Alps-Azure Coast, and the Italian regions of Liguria, Emilia Romagna and Lombardy. The former French region of Languedoc-Roussillon qualified as well prior to being merged with Midi-Pyrenees to form Occitania (I have been to some departamental roads in the part formerly known as Midi-Pyrenees). No communities of Spain currently qualify. Bonus points for the Veneto region of Italy, the only part of the world where I actually have been on a State Highway .

[Roadsguy]

None for me. For all the states I've been to, I've been on at least one state route, even counting DC with 295.

I've been very close to not having been on a state route in some states, though. In Ohio and West Virginia, I've only been on brief sections of SR 236 and WV 10, respectively, adjacent to Interstates. I thought at first that Indiana would qualify with I-265 having replaced IN 265 at the time that I drove it (albeit not yet on signage), but then I remembered the brief concurrency with IN 62.

[US 89]

Of the 35+DC states I’ve been to:

DC - haven’t been on DC 295
Indiana - quick loop from Louisville, up 65 and back down 31
Iowa - briefly dropped into the state on US 18
Michigan - airport layover
Minnesota - airport layover
New Hampshire - went through on I-95 and I don’t think we exited anywhere
New Jersey - boat only
New York - no road mileage, though I’ve crossed 9W on foot

It’s worth noting that this is impossible in a state like Georgia, where every interstate or US route also has an underlying state route designation. Interstates have unsigned SR 4xx numbers, but the state routes concurrent with US Highways are almost always signed, and in many cases are actually the better-known name for the roadway - for example, US 23 north of Gainesville is primarily signed as SR 365, and US 19 north of Atlanta is always referred to as 400.

[DandyDan]

I believe I have never been on a state highway in Maryland. The entirety of my visit to Maryland was going from Alexandria, VA to Baltimore to see the Orioles and that was basically all Interstate travel. This was in 2001. I don't think I was on a signed state highway in Kentucky in 2003, but I was on the Pennyrile Parkway. I can't tell you about my 1978 trip through North Dakota, Montana and Wyoming. All other states have at least one state highway travel I have been on.

[deathtopumpkins]

Hmm let's see... in order by miles traveled:

MA - I, US, SR
NY - I, US, SR
ME - I, US, SR
NH - I, US, SR
VA - I, US, SR
VT - I, US, SR
PA - I, US, SR
CT - I, US, SR
OH - I, US, SR
NC - I, US, SR
MD - I, US, SR
IL - I, US, SR
OK - I, US, SR
IN - I, US, SR
NJ - I, US, SR
RI - I, US, SR
MI - I, US, SR
CO - I, US, SR
TN - I, US, SR*
MO - I, US, SR
KS - I, US, SR*
CA - I, US, SR
NE - I, US*, SR*
NM - I, US, SR
SC - I, US, SR
WI - I, US, SR
WV - I, US, SR
IA - I, US*, SR*
AR - I, US*, SR
DE - I, US, SR
AL - I, US*, SR*
KY - I, US*
TX - I, US*, SR*
MS - I, US*, SR*
GA - I, US, SR*
FL - I, US, SR
LA - I, US*
DC - I, US, SR

* only because of an interstate multiplex

Looks like my winners are KY and LA! Frankly I'm shocked given the size of these states' state highway networks that I haven't at least been on one concurrent with an interstate. In TN, KS, NE, IA, AL, TX, MS, and GA I have only been on state routes concurrent with interstates or US routes.

[hbelkins]

My only possibilities would be Colorado, Utah, Idaho, Wyoming, and South Dakota. And that's only if there were no state concurrencies on any of the US or Interstate routes I was on in those states.

[jp the roadgeek]

All of New England, NY, NJ, PA, DE, MD, DC, VA, WV, FL, HI are out.  MO is out because I never left the airport.

NC: It was 1982 and not sure if the motel I stayed at was on a US or state route.  Otherwise, never left I-95 or US 15/501
GA: Unless we count hidden state routes (I-95), I never left I-95 or Hartsfield-Jackson
SC: I-95 and US 15/501 (to go to Pedro's), but no state routes
MS: Unless you count a tiny segment of MS 15 within the I-10/I-110 interchange, none.  Only I-10, I-110, and US 90.
LA: Was on I-10 and a piece of US 61, but no state.
IN: Was on I-65/I-70, but no state.

[Roadgeekteen]

West Virgina. Just drove through on I-81

[Eth]

Mine are all in the northeast: Delaware, New Jersey*, New York, Rhode Island (I-95 for all of those), and Vermont (I-89 and US 2).

(* NJTP notwithstanding; no signed SR number)

I believe the exact opposite of this may be Ohio, where I think I've been on a state route (either OH 32 or OH 618) and have definitely not been on any other numbered route.

[Rothman]

I have driven on interstates in 49 states.  The only state I can think of where I haven't been on a state highway may be Nebraska, unless there's a concurrency on I-80 I am not remembering.

Only have been on a state highway in Oklahoma due to concurrencies on I-40.

All other states I've been off the beaten path in.

[RobbieL2415]

DC: been on I-66 and I-395, but not DC 295.

[dlsterner]

I have been to 33 states (counting DC as a "state").  States that I have been on an Interstate/US highway but not a state highway:

Arizona - only US 93
Louisiana - only I-10 and US 190
Mississippi - only Interstates 10, 20, 55, 110, 220, US 49, 51, 90
Rhode Island - only I-95, I-295, US 6

Four.

Some close calls, like Massachusetts with just MA 2, on its concurrency with I-91, being the only one.
Also went through Rhode Island on family vacation at age 7 - possible but not that likely that I may have hit some then.
Also three states with no Interstate or US highways either, but the OP explicitly excludes those.

[sbeaver44]

Out of 39 States + DC
Colorado -- US 160 and US 491 only
Nebraska -- looks like I used 28H Link in my brief journey through Omaha.  I don't fully understand the Nebraska hierarchy, but I assume 28H Link is a state highway?

[DandyDan]

Nebraska -- looks like I used 28H Link in my brief journey through Omaha.  I don't fully understand the Nebraska hierarchy, but I assume 28H Link is a state highway?

All the link and spur highways you see in Nebraska are state highways. I still think they should just give them regular numbers.

[Jim]

I've traveled state highways in all 50 plus DC, but it looks like my only state highway mileage in Idaho and Montana was concurrent with an Interstate.

[SSOWorld]

DC - was on US-29 only. (the 48 states have miles on all levels)

[deathtopumpkins]

I have driven on interstates in 49 states.  The only state I can think of where I haven't been on a state highway may be Nebraska, unless there's a concurrency on I-80 I am not remembering.

There is. NE 10 near Kearney.

[Rothman]

I have driven on interstates in 49 states.  The only state I can think of where I haven't been on a state highway may be Nebraska, unless there's a concurrency on I-80 I am not remembering.

There is. NE 10 near Kearney.

Well, no state qualifies for me, then.

[DJ Particle]

We can rule out MA, MN, and NY, as I spent significant time in all 3 states during my life.
We can also rule out WI (29, 23, 58, 35), IA (100, 930, 27, 58), RI (10, 24, 101, 114, 138, 195 [when it existed]), and CT (72, 372, 9, 85, 2, 11, 101)

Let me think of my longest road trips...

IL:  nope...  (72, 58, 53, 142, 242)
IN:  nope...  IN-49 has a short multiplex with I-70 that I've drove on.
OH:  nope... OH-2 has its short multiplex with I-90
PA:  does pre-I-86 PA-17 count?
NJ:  nope... (35, 18, 444, 700, 17)
DE:  I think I found one!  Only ever drove on I-95 and I-295 in DE.
MD:  nope... (295)
DC:  nope... (295)
VA:  nope... (233)
MO: nope... (27)
KY:  Aha!  Only been on I-24 and its multiplex with I-69
TN:  nope... TN-2 has a short multiplex with I-24
GA:  nope... I-75 is also GA-401
FL:  nope... (31)

And one more state...
CA:  nope... (1, 55, 237)

So...just Delaware and Kentucky.

[NWI_Irish96]

IN:  nope...  IN-49 has a short multiplex with I-70 that I've drove on.

IN 49 does not go anywhere near I-70.

[JCinSummerfield]

VA, NC, SC, GA, AL

My trip from Parkersburg, WV to Alabama.