States with a 3dus, but no root 2dus

[Darkchylde]

One more I felt like looking up: US 218 enters Minnesota, but US 18 doesn't.

[NE2]

US-163 is not a child of US-63; it's just an independent number chosen to upgrade UT-163.

Not quite. US 163 replaced SR-47 (which continued to exist, unsigned, until 1977). SR-163 was created in 1986 on a new state highway.
http://www.udot.utah.gov/main/uconowner.gf?n=1246329301645072 (large PDF)

[topay]

US 522 and US 340 in Virginia.  They also happen to join up for a handful of miles in and near Front Royal.

[NE2]

There is no US OAT in the Perkins Union, yet US GOAT doesn't cross from Alanland.

[Molandfreak]

169 in MN runs almost 300 miles, where 69 barely runs for 10 miles. 69 should have taken over MN 13 and MN 21, and then the rest of 169.

[roadman65]

US 522 and US 340 in Virginia.  They also happen to join up for a handful of miles in and near Front Royal.

Also WV as well.

US 301 in DE as US 1 does not enter the First State.
US 231 in Florida
US 331 in Floridad
US 221 in GA and FL
US 278 in Arkansas

[Rover_0]

US-163 is not a child of US-63; it's just an independent number chosen to upgrade UT-163.

Not quite. US 163 replaced SR-47 (which continued to exist, unsigned, until 1977). SR-163 was created in 1986 on a new state highway.
http://www.udot.utah.gov/main/uconowner.gf?n=1246329301645072 (large PDF)

The reasoning behind SR-163 in Utah was to extend US-163 east along what's now SR-162 and CO-41 to US-160 near Cortez, CO and west along US-160, AZ-98, US-89, US-89A, AZ-389, UT-59, and UT-9 to I-15 near Hurricane, UT. There was an earlier proposal that had US-163 going north with US-89 and west along UT-14 to Cedar City. I'm not entirely sure why UDOT didn't pursue a US-163 extension along SR-163, but it may have had something to do with then-SR-262 not being built or that the AASHTO designation wasn't changed to match up US-163 to SR-163 when it was. Not that it stopped UDOT from signing US-89A solely as SR-11 from about 1994-2011 or "ending" US-189 at US-40 in Heber City, but still.

And you think US-163 as originally concocted (Kayenta-Crescent Jct.) or even as it is now was bad...unless the plan was to renumber it upon making it east-west. In that case it should've been US-x60 or US-x64 IMO.

[The High Plains Traveler]

New Mexico:
[...]
US-285* (according to NMDOT)
[...]

That's all off the top of my head.

I-25 in New Mexico must be a sliver of Alanland, because U.S. 85 along it does and does not exist.

[hbelkins]

US 522 and US 340 in Virginia.  They also happen to join up for a handful of miles in and near Front Royal.

Also WV as well.

Actually, US 22 and US 40 cross the northern panhandle of WV. Their children cross the eastern panhandle.

US-491 exists in NM, CO, and UT.  US-91 does not exist in NM and CO, and it is on the other side of the state in UT (even its old extended format was elsewhere).  US-191, which is US-491's logical parent, does not enter CO or NM either.

The original number of that route qualifies as well. US 66 never entered Colorado or Utah.

Speaking of Colorado, add US 160 to the list. US 60 never entered Colorado.

And then there's US 321 and US 421 in Tennessee. Tangentially related, US 25E used to clip the westernmost tip of Virginia. Its parent, US 25, never entered Virginia.

[roadman65]

i forgot that one about US 22 and US 40 both entering the other panhandle of WV.  However, I just remembered that US 522 is in Maryland in which US 22 is not.  Although US 522 is less than two miles in MD without even one single stoplight, it still enters it which many of us might overlook that one.

[DandyDan]

US 385 goes through Nebraska, while US 85 does not.

[Revive 755]

Indiana
Used to have US 460

Kansas
US 160
US 166*

Missouri
US 166*
US 275

[amroad17]

US 123 in South Carolina, in which US 23 never enters.
US 129 in Tennessee, in which US 29 never enters.
US 158 in North Carolina, in which US 58 never enters.  US 158 does not even meet its parent!  It does connect to US 258.
US 206 in New Jersey, in which US 6 never enters. (Close by about 1/4 mile)
US 209 (and formerly US 309) in PA, in which US 9 never enters.
US 224 in PA, in which US 24 never enters.
Currently, US 311 in NC (until it is extended to VA), in which US 11 never enters.
US 421 in Indiana and Kentucky, in which US 21 never enters.

[US71]

Arkansas has US 425 that has no parent. Also US 412 (again, no parent).

[jas]

US 202 only goes through three of the states, New York, New Hampshire, and Maine, that its parent road, (US 2), also goes through.

[Molandfreak]

Kansas
US 160
US 166*

US 400

[roadman65]

Kansas
US 160
US 166*

US 400

US 400 is like US 101, both in their own mind are two digit routes, but using a third one for some odd reason.