It has to be obvious, like I-91 at the NH/VT border (along with US 5).
These will probably more common when the state border is a river.
IL 1
I-29 in Nebraska, and across the border, US 75
All of US 166
All of NY 22, and across the border, US 7
I-80 and I-90 in Indiana
US 52 northwest of Williamson WV, probably the longest parallel to a state border.
Eastern segment of Mexico 2 (yes, it's still a state border!)
WI 11, WI 35
the western segment of MX-2 runs within 10 feet of the border in some places between Sonoyta and San Luis Rio Colorado.
US 23 in Kentucky would count. So too would the various segments of KY 8.
And so would WV 2, which but for a few deviations runs mostly within sight of the Ohio River and Ohio state line for the entire length of its border.
PA 32 and NJ 29 on either side of the border. Further south, I-95 on the PA side of the NJ border from the non-interchange with the PA Turnpike to the Delaware state line. Is the ocean a state line? If so, Garden State Parkway parallels it from the Driscoll Bridge south to its terminus.
MSR 120
DE 92 (Naamans Road) and DE/PA 491 (Naamans Creek Road) run mostly parallel to the DE-PA border.
The US 89/ID 61/WYO 89/UT 30/UT 16/WYO 89 chain of routes
AR 43/OK 20
DE 54/MD 54, which spends about 10 miles with the state line right down its center.
Quote from: NE2 on October 09, 2013, 04:58:15 PM
MSR 120
Might want to specify the states for people who don't know every MSR. (It's Indiana/Ohio, with the Michigan section connecting them decommissioned in 1961.)
US 1 and A1A in Florida. :-P
NJ35
Washington SRs 4 and 14. And US 30 and I-84 across the river in Oregon.
M-185
Quote from: NE2 on October 09, 2013, 07:08:41 PM
M-185
M-185 may follow the shoreline of Mackinac Island, but it's nowhere near the Michigan state line. Now US 2 roughly parallels the state line between Ironwood and Iron River before running further away and turning to cross back into Wisconsin.
every road around each Hawaiian island
SD 109 and part of US 18 West River.
Quote from: 1 on October 09, 2013, 04:02:53 PM
It has to be obvious, like I-91 at the NH/VT border (along with US 5).
These will probably more common when the state border is a river.
IL 1
I-29 in Nebraska, and across the border, US 75
All of US 166
All of NY 22, and across the border, US 7
I-80 and I-90 in Indiana
US 52 northwest of Williamson WV, probably the longest parallel to a state border.
Eastern segment of Mexico 2 (yes, it's still a state border!)
US 9 (New York), then. It parallels the border as obviously as NY 22 does, just further to the west. So does I-81, for that matter. Methinks there may be a missing criterion here...
Damn. I missed that.
I-2 and I-8 come to mind.
NR44, Bruxner Hwy
NR42, Cunningham Hwy
NR58, Riverina Hwy
B400, Murray Valley Hwy
NY 120A goes right along the New York-Connecticut border.
Almost every road in CO East of I-25.
Quote from: bulldog1979 on October 09, 2013, 09:56:46 PM
Quote from: NE2 on October 09, 2013, 07:08:41 PM
M-185
M-185 may follow the shoreline of Mackinac Island, but it's nowhere near the Michigan state line. Now US 2 roughly parallels the state line between Ironwood and Iron River before running further away and turning to cross back into Wisconsin.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi3.kym-cdn.com%2Fphotos%2Fimages%2Foriginal%2F000%2F483%2F894%2F463.jpg&hash=8759fe97fc89c99cdf26aba516022e73b0d26a6b)
...since people started counting oceans as state boundaries.
Wouldn't every road that runs the same direction as any one of a state's state line count as a parallel road, regardless of it's location within the state?
NM 9 crawls across the Bootheel of NM, much of it close to the Mexican border. AZ 80 hugs the Mexican border from Douglas to Bisbee. AZ 95 follows the California border for most of its route.
US 5 and I-91 are pretty close to the NH State Line (Connecticut River) from the MA Line to St. Johnsbury, VT.
US 3 travels about 30 or so miles on the east side of the Connecticut River in NH after US 5 and I-91 part ways on the other side in Vermont.
Does not the I-80/90 Toll Road in Indiana follow close to the MI state line for over 100 miles or more?
Yes on I-80/90, being within eyeshot of Michigan. Also, don't forget about OH-7, running along Ohio's SE & E border.
Quote from: roadman65 on October 10, 2013, 01:38:28 PM
US 5 and I-91 are pretty close to the NH State Line (Connecticut River) from the MA Line to St. Johnsbury, VT.
That was mentioned in the original post!
I-68 in West Virginia and Maryland runs close to, but never enters, Pennsylvania.
Quote from: cpzilliacus on October 10, 2013, 03:56:11 PM
I-68 in West Virginia and Maryland runs close to, but never enters, Pennsylvania.
similarly, US-18 never enters Nebraska.
US-52, however, does enter Kentucky.
HB mentioned KY 8.
US 50 parallels the Kentucky state line for a period from south of the junction with Ohio SR 125, through downtown Cincinnati, out to just south of Ohio SR 128 near Cleves, Ohio. If we ignore that deviation to the north (it only lasts about a mile or so), then US 50 can be said to parallel the KY state line into Indiana to just outside of Aurora, Indiana, where it finally leaves the Ohio River behind for good.
Quote from: agentsteel53 on October 10, 2013, 03:58:35 PM
similarly, US-18 never enters Nebraska.
But it gets really close.
CA-161 between US 97 and CA-139
https://www.google.com/maps?ll=41.972764,-121.714783&spn=0.311402,0.449066&t=m&z=11
Two that just popped into my mind after reading the links in the WV railroad vs. log truck thead. WV 90 and WV 24. Both parallel the Maryland state line.
US 58 never gets more than about 20 miles from the VA-NC-TN border throughout its 508-mile length.
SR-184 (Alexis Road) is the last major east-west highway in Toledo before you cross into Michigan. Most, if not all of SR-184 is less than 3/4-miles from the border.
Quote from: 1 on October 09, 2013, 04:02:53 PM
I-29 in Nebraska, and across the border, US 75
Other way around. I-29 is on the Iowa side, US-75 crosses the border in Sioux City and parallels the river on the Nebraska side from there south.
Apologies if this has already gotten a mention, but Iowa Highway 9 parallels the Minnesota state line.
US 460 between Petersburg and Suffolk parallels the south part of the Nevada-California border.
Quote from: hbelkins on October 13, 2013, 06:54:46 PM
Two that just popped into my mind after reading the links in the WV railroad vs. log truck thead. WV 90 and WV 24. Both parallel the Maryland state line.
Especially W.Va. 90 (because it's longer than W.Va. 24, though not especially long). It runs through mostly wild and undeveloped (but frequently mined-out) lands from U.S. 219 relatively close to the upper reaches of the Potomac River and ends a stone's throw from the Potomac just east of Bayard at U.S. 50.
US 52 closely hugs the Ohio River from downtown Cincinnati until it finally crosses it into Huntington WV. It covers about 90% of the OH/KY border.
OH 49 follows the Indiana border from Greenville to the Michigan line where it becomes M 49. It covers about 2/3 of the OH/IN border.
The OH/MI border is really all that extensive, but it does have US 20 following it pretty closely most of the way.
The Lake Erie shoreline isn't really a border, but if we want to count routes following a states outline then OH 2 would get the nod here for covering most of that.
And as mentioned previously, OH 7 is the king of border roads in Ohio, covering pretty much the entire WV and PA borders.
I-8, CA 94 and CA 98 parallel the California-Mexico Border.
What about ON the border, as US 71 thru Texarkana? TX and AR.