Longest State Route You Haven't Been On.

[pianocello]

It's been five years since I posted here, so I'll check in with some new states:

Florida: SR 30 (11th-longest). Longest standalone: SR 70 (second-longest of those that aren't hidden designations for Interstates or US Routes)
Illinois: IL 127 (12th-longest)
Indiana: SR 9 (5th-longest, for now)
Iowa: IA 9 (2nd-longest)
Michigan: M-25 (7th-longest)
Wisconsin: WIS 27 (5th-longest)

As far as I know, I haven't been on the longest route of any other states, unless there's an overlap I'm not aware of.

[74/171FAN]

PA: PA 414 (77.32 miles)
NY: NY 30 (291.13 miles)
NJ: NJ 70 (60.22 miles)
VA: VA 57 (86.45 miles)
MD: MD 32 (50.63 miles)
NC: NC 27 (197.17 miles)
DE: DE 16 (30.16 miles)  (I am looking to get a full clinch of DE eventually.)
WV: WV 20 (253.65 miles)
OH: OH 4 (209.47 miles)

*Mileage is based on Travel Mapping

I have not driven enough mileage in other states to bother.

Updating since DE is fully clinched, and I have traveled on NY 30, NJ 70 (clinched), MD 32 (clinched), WV 20, and OH 4 since my original post.  I still do not think that any other states are worth doing at the moment besides AZ since I did do a full-on trip there about a year ago.

NY:  NY 3 (244.64 miles)
NJ:  NJ 72 (29.35 miles)
MD: MD 224 (26.71 miles) 
WV:  WV 10 (137.71 miles)
OH: OH 13 (165.09 miles, feels like one of the few north-south routes that I have not snuck in at least a concurrency on)
AZ: AZ 87 (286.67 miles, longest route in the state, was on my original route plan in September 2021, but got cut in the midst of redoing my route plan so that I could close the gap on US 60 between Phoenix and Globe on the Friday of that week as US 60 was closed for a bridge project on Tuesday)

Updating since MD is fully clinched in Travel Mapping now, and a few other states are worth adding IMO:

PA: PA 247 (49.74 miles, I gained mileage on PA 414 back in December 2022 while clinching PA 287)
NJ: NJ 36 (24.65 miles, I am looking to finish NJ soon at this point)
OH: OH 47 (105.80 miles, I was just east of the eastern terminus while clinching US 23 between Toledo and Columbus last month)
FL: FL 70 (150.29 miles)
IN: IN 56 (195.46 miles)
KY: KY 52 (159.86 miles)
GA: GA 7 (217.54 miles)
IL:  IL 16 (175.42 miles)
TN: TN 100 (156.71 miles)
SC: SC 34 (185.22 miles)
AR:  AR 7 (297.15 miles, longest)

I do not think I have done enough travel in other states to add them yet though LA 1, M-28, and MO 5 are the longest and my longest for those states.

Today's update though my list file has not been updated yet to include PA 247.

PA: PA 187 (41.78 miles)
VA:  VA 72 (43.78 miles)

[boilerup25]

NJ: NJ 68 (8 miles)
CA: CA 190 (178 miles)

[Dough4872]

Pennsylvania: PA 18 at 205 miles
New Jersey: NJ 23 at 52.63 miles
Delaware: DE 17 at 8.30 miles
Maryland: MD 4 at 64.85 miles

[74/171FAN]

Delaware: DE 17 at 8.30 miles

I honestly would have expected DE for you to be something a bit longer than DE 17.

[dfilpus]

North Carolina: NC 12, 14th longest.

Since the, I've driven all of NC 12 from Hatteras north. Now the answer is NC 10, 48.3 mi, #54 in state.

[formulanone]

I did a recount in Travel Mapping; was off by a few here and there and had a few new ones to add...

AL: 63 (38th, excluding hidden SRs)
FL: 65 (17th, excluding hidden SRs)
TN: 131 (22nd, excluding hidden SRs)
MS: 341 (36th)
NC: 12 (14th)
TX: 207 (6th)
IN: 66 (12th)
LA: 4 (5th)
PA: 144 (11th)
IL: 16 (8th)

[cenlaroads]

In the two states I've driven in the most:

LA:  LA 308
TX:  TX 16

[formulanone]

Drove a part of Alabama SR 63 today, so now the longest SR I haven't driven on is 165. 

[74/171FAN]

PA: PA 247 (49.74 miles, I gained mileage on PA 414 back in December 2022 while clinching PA 287)
NJ: NJ 36 (24.65 miles, I am looking to finish NJ soon at this point)
OH: OH 47 (105.80 miles, I was just east of the eastern terminus while clinching US 23 between Toledo and Columbus last month)
FL: FL 70 (150.29 miles)
IN: IN 56 (195.46 miles)
KY: KY 52 (159.86 miles)
GA: GA 7 (217.54 miles)
IL:  IL 16 (175.42 miles)
TN: TN 100 (156.71 miles)
SC: SC 34 (185.22 miles)
AR:  AR 7 (297.15 miles, longest)

All NJ routes are now clinched.

PA is now PA 670 (21.28 miles).

[pderocco]

Based on TravelMapping's approximate mileage, these are the longest in the states I've explored the most:

CO-96   207.05
CT-10    54.23
ID-75   166.18
MA-57    43.16
ME-16   186.8
MT-59   197.84
NH-12    62.1
NM-120  116.91
NV-318  112.24
NY-37   127.48
OR-31   122
PA-18   201.01
RI-3     30.6
UT-21   108.54
VT-14   107.1
WA-410  104.09
WY-59   175.69

This leaves out CA and AZ because I've driven all of them.

[Dough4872]

Pennsylvania: PA 18 at 205 miles
New Jersey: NJ 23 at 52.63 miles
Delaware: DE 17 at 8.30 miles
Maryland: MD 4 at 64.85 miles

Been on PA 18 now, so my longest in Pennsylvania is PA 8 at 148.6 miles

[LilianaUwU]

QC: QC 167 at 548.85 km
ON: ON 101 at 479.66 km
NB: NB 105 at 272.14 km
NS: NS 101 at 310.89 km

Interestingly, two provinces' longest routes I don't have are numbered 101. NB 105 is the one that would be the most realistic for me to get some mileage.

[thspfc]

I've driven through an intersection with WI-80. I was on WI-80's pavement, I'm counting it.

So then it's WI-81, which is 124 miles long, the 24th longest state trunkline.

It's not WI-81, I've been on the Monroe bypass.

Final answer is the 81.5-mile WI-40, the 33rd longest.

I was on WI-40 last month, so make it the 68-mile WI-93.

Pretty sure my Wisconsin answer is now WI-58, at 54 miles and 48th-longest. I've made much less progress in Minnesota, the answer being the 265-mile MN-30, the 4th-longest.

[TBKS1]

In Arkansas it would be AR 141. There's two sections to a combined length of about 55 miles long.

[NWI_Irish96]

IN: none
IL: IL 127, 168.4 miles long
MI: M-123, 96.7 miles long
WI: WI 77, 138.8 miles long

[ModernDayWarrior]

The longest Missouri state route I've never been on appears to be MO 46, the 30th-longest MO state route at 85.9 miles.

[dlsterner]

For the states that I have either lived in, or have significant driving mileage in:

Maryland:  MD 12 (about 30 miles) - one on my planned road trips will get some (if not all) of it.
Pennsylvania:  PA 18 (about 200 miles; longest in the state)
Florida:  FL 50 (about 120 miles; not sure how I missed it while I was there)
Virginia:  VA 40 (about 225 miles)
Delaware:  DE 30 (about 45 miles)
Washington DC:  None 

For all states, I'm sure it would be MT 200.

Updating after a few years...

Maryland:  MD 224 (about 27 miles)
Delaware:  DE 24 (about 41 miles)  (DE 30 was truncated in 2022)

Another update, having since travelled parts of MD 224 and DE 24 ...

Maryland:  MD 194 (about 24 miles)
Delaware:  DE 16 (about 30 miles)

[Road Hog]

The two longest state highways in Arkansas are AR 7 and AR 16. I'm proud to say I have traveled the concurrency of both from Pelsor in Pope County to Lurton in Newton County.

Sadly, I have never traveled AR 3, which appears to have become US 79 circa 1940. (I have driven US 79 several times.)

Never had the occasion to drive AR 17 from Brinkley to Tuckerman. (114.28 miles according to AA Wiki, although that seems long.)

[Jim]

While we're all updating...

I'll keep my list to my home state, the two others where I've lived, and Florida, where I've spent a lot of time.

TM doesn't show travels on NY 25 or NY 417 but I know I have at least some in the long-ago past on NY 25 and probably at least hit a short segment of NY 417, so I'm not counting those.  Since my last post here, I have traveled parts of old winner NY 19 a few times.  I don't know why I didn't previously count FL 65, which is longer than old answer FL 77 (which I have also since traveled).  Massachusetts and New Mexico are unchanged.

New York: NY 240, 51 miles and 58th longest.
Massachusetts: MA 27, 71 miles and 7th longest.
Florida: FL 65, 72 miles, 17th longest (counting the three longest A1A segments as separate routes).
New Mexico: I have not traveled the 4 longest routes at all, starting with NM 120 at 117 miles.

[oscar]

I'm still scouring Travel Mapping for my answer. So far, the longest state route I haven't been on is ND 50 in western North Dakota, about 100.70 miles long. A close second is OK 5, at about 99.44 miles.

Now up to 134.13 miles (WA 26).

[drebbin37]

Updates in italics.  For the 48 states I've driven in:

Haven't Been on Longest
TX 16 (567.00 miles)
ND 200 (417.59 miles)
WA 20 (416.09 miles)
OK 3 (389.94 miles)
AR 7 (297.15 miles)
NC 24 (281.03 miles)
OR 140 (243.70 miles)
ID 75 (166.18 miles)
NM 120 (116.92 miles)
NV 318 (112.24 miles)

Haven't Been on 2nd Longest
CA 99 (432.06 miles)
SD 20 Main (402.29 miles)
NE 2 Main (373.57 miles)
MT 3 (224.06 miles)
SC 34 (185.22 miles)
WY 59 (175.70 miles)
TN 100 (156.71 miles)

Haven't Been on 3rd Longest
MN 65 Main (273.34 miles)
UT 12 (123.39 miles)

Haven't Been on 4th Longest
MS 12 (199.96 miles)
AZ 264 (153.70 miles)

Haven't Been on 5th Longest
CO 141 (153.85 miles)
FL 50 (115.82 miles)

Haven't Been on 6th Longest
GA 26 (274.19 miles)

Haven't Been on 7th Longest
AL 25 (169.37 miles)
DE 16 (30.43 miles)

Haven't Been on 8th Longest
LA 10 Ville Platte (112.97 miles)
MD 32 (50.63 miles)

Haven't Been on 9th Longest
WI 54 (242.42 miles)
MI 50 (142.22 miles)
KY 70 Madisonville (137.75 miles)
WV 7 (100.48 miles)

Haven't Been on 10th Longest
PA 56 (106.54 miles)

Haven't Been on 11th Longest
VA 14 (70.26 miles)

Haven't Been on 12th Longest
IA 10 (106.40 miles)

Haven't Been on 13th Longest
MO 94 (132.73 miles)

Haven't Been on 16th Longest
KS 148 (87.82 miles)

Haven't Been on 24th Longest
IL 104 (127.32 miles)

Haven't Been on 25th Longest
IN 38 (95.68 miles)

Haven't Been on 34th Longest
OH 95 (89.30 miles)

Haven't Been on 46th Longest
NY 25A (71.96 miles)

Haven't Been on 51st Longest
ME 227 (24.32 miles)

Have Been on All
MA, NH, CT, VT, RI, NJ

[WillWeaverRVA]

Virginia: VA 42 (VA 40 is the longest and I've been on it)
Maryland: MD 2
Pennsylvania: PA 18
North Carolina: NC 24
South Carolina: SC 34 (SC 9 is the longest and I've been on it)
Delaware: DE 15
New Jersey: NJ 444/GSP
Ohio: OH 7
Michigan: M-28
Illinois: IL 1 (not counting IL 110)
California: CA 299

[Hunty2022]

This list is due for updates:

Haven't been on longest:
GA-11
WV-20
PA-18
DC-295

Haven't been on 2nd longest:
TN-15
SC-34
MD-313
DE-9

Haven't been on 3rd longest:
NC-42

Haven't been on 4th longest:
FL-10

Haven't been on 6th longest:
VA-10

[vdeane]

I've clinched everything signed in NY (unless there are any new unsigned reference routes that we don't know about), so for me the longest state route in NY I haven't clinched is reference route 952P (7.64 miles), Forrest Avenue from the PA border to NY 60 in Jamestown.

Using Travel Mapping to (approximately) identify the signed routes for my top 10 jurisdictions (other than NY) by clinched mileage:
-Pennsylvania: PA 18 (201.01 miles)
-New Jersey: NJ 49 (54.48 miles)
-Massachusetts: MA 62 (78.73 miles)
-Vermont: VT 108 (44.10 miles)
-Maine: ME 16 (186.80 miles)*
-Québec: QC 167 (341.04 miles)**
-Connecticut: CT 20 (30.42 miles)
-Maryland: MD 5 (74.70 miles)
-Florida: Florida's Turnpike (314.31 miles)***
-New Hampshire: NH 114 (58.71 miles)

*Travel Mapping shows ME 6 as unclinched, but I've actually been on a tiny piece of it in Topsfield to view Eris.
**Excluding the main section of QC 138, which is listed separately on TM due to the ferry in Tadoussac.
***Excluding the Turnpike and US routes, the longest is FL 60 (163.52 miles).