Auxiliary state roads whose numbers are derived from highways in another state

[KCRoadFan]

In Vermont, Route 22A is one of the main roads in the northwest part of the state, connecting Fair Haven with Vergennes and forming a key part of the route between Burlington and Saratoga Springs (and thus Albany).

However, despite there being a VT 22A, there is no VT 22. Why the number, then? Simple: because VT 22A is an extension of NY 22A, which branches off NY 22, a major road along New York State's eastern border. (Incidentally, VT 22A is far longer than NY 22A.)

Elsewhere in New England, MA 114A (which goes through Seekonk along Massachusetts' border with Rhode Island) does not branch off MA 114, which is in the northeast part of the state connecting Lawrence and Peabody; rather, MA 114A is the continuation of RI 114A, which branches off RI 114. Again, MA 114A is longer than RI 114A.

Throughout the country, what examples are there of auxiliary state highways - either 3-digit numbers or numbers with a letter suffix - where the route that the number derives from is in another state, and the branch route crosses the state line (especially cases, such as those mentioned above, where the longer portion of the branch route is in the "unconnected"  state)?

[andrepoiy]

In Ontario, Highway 148 is a 7 km highway that is essentially an extension of Quebec Route 148. We don't really have "auxiliary routes" so yeah.

There's also a lot of examples of this within county routes, but I think that's out of the scope of this thread.

[deathtopumpkins]

New Hampshire 113B is a branch off of Maine 113, which itself enters New Hampshire, but is not a New Hampshire route - NH has its own separate 113 that is (somewhat confusingly) only 10 miles away.

Vermont 10A is a short continuation of New Hampshire 10A, a spur off New Hampshire 10, and unrelated to Vermont 10, which is about 30 miles to the south.

[Dirt Roads]

As best as I can tell, West Virginia only has one: WV-527 was originally the old route of US-52 in Huntington and is derived from OH-7.

I thought that were two others that turned out to be false hopes:  One was WV-29 and WV-9/VA-9.  The other was VA-259/WV-259 and the former WV-59/VA-59.  In both of these cases, it turns out that the West Virginia routes were there before Virginia matched the numbers.  In the case of the latter, WV-59 was the only remaining dirt road posted as a state highway until it was decommissioned a few years ago.

[hbelkins]

As best as I can tell, West Virginia only has one: WV-527 was originally the old route of US-52 in Huntington and is derived from OH-7.

I thought that were two others that turned out to be false hopes:  One was WV-29 and WV-9/VA-9.  The other was VA-259/WV-259 and the former WV-59/VA-59.  In both of these cases, it turns out that the West Virginia routes were there before Virginia matched the numbers.  In the case of the latter, WV-59 was the only remaining dirt road posted as a state highway until it was decommissioned a few years ago.

How about WV 635? It's obviously numbered as such because it connects to Virginia secondary route 635, but I don't see the point of it being assigned a primary route designation. It could be CR 635, the same way that CR 857 is signed as an extension of PA 857.

[Mapmikey]

As best as I can tell, West Virginia only has one: WV-527 was originally the old route of US-52 in Huntington and is derived from OH-7.

I thought that were two others that turned out to be false hopes:  One was WV-29 and WV-9/VA-9.  The other was VA-259/WV-259 and the former WV-59/VA-59.  In both of these cases, it turns out that the West Virginia routes were there before Virginia matched the numbers.  In the case of the latter, WV-59 was the only remaining dirt road posted as a state highway until it was decommissioned a few years ago.

VA 259 was there before WV 259.

Another example is WV 311, which was WV 81 renumbered to match VA 311.

WV 618 is another example.

I would argue WV 527 derives from US 52 instead of OH 7.  Although a different way of looking at it is that it is not a continuation of WV 152 because OH 152 already exists elsewhere and thus derives from Ohio's situation.

WV 102 derives from VA 102 who wanted to renumber VA 85 because of the creation of I-85.

WV 956 is also an example, matching the older MD 956 which replaced MD 9 before WV made its side primary.

WV 127 is also a renumbering of WV 45 because Virginia would never put into its system a primary route connecting the two WV 45s.

I do not know who decided upon 598.

[NE2]

598 was probably Virginia, wanting a high number but not being able to use 599 (placeholder for construction projects).
Anyway, I can't think of any more of what the OP asked for.

[Dirt Roads]

Throughout the country, what examples are there of auxiliary state highways - either 3-digit numbers or numbers with a letter suffix - where the route that the number derives from is in another state, and the branch route crosses the state line (especially cases, such as those mentioned above, where the longer portion of the branch route is in the "unconnected"  state)?

My understanding is that the OP was looking for spin-offs of a route number from another state.  The specific example was VT-22A, which is a spin-off of NY-22 (just happens to be a continuation of NY-22A).  Continuation of non-spinoff route numbers like WV-102, WV-311, WV-598, WV-618, CR-635, LSR-857 and WV-956 don't make the cut.  But WV-161 would qualify if VA-16 had been there before WV-16.  But alas, Virginia renumbered to match West Virginia so it's another near miss.

So how about this one.  SC-905 was originally a spin-off from SC-9.  It was extended to the North Carolina border in the early 1940s and North Carolina continued the route as NC-905 in the late 1950s.  So NC-905 is a legit spin-off of SC-9.  And if you want to overthink this one, then the entire cluster of NC-904, NC-905 and NC-906 could be considered spin-offs of SC-9.

[Bruce]

A few BC highways were numbered based on WA highways using the pre-1964 numbering system. An example: BC-22 and BC-22A connect with SR 25 (former WA-22) and former SR 251 (WA-22A).

[Big John]

A few BC highways were numbered based on WA highways using the pre-1964 numbering system. An example: BC-22 and BC-22A connect with SR 25 (former WA-22) and former SR 251 (WA-22A).

Was BC-99 based on an an extension of US 99?

[Bruce]

A few BC highways were numbered based on WA highways using the pre-1964 numbering system. An example: BC-22 and BC-22A connect with SR 25 (former WA-22) and former SR 251 (WA-22A).

Was BC-99 based on an an extension of US 99?

Yes, as was BC-97 (US 97), BC-395 (US 395), BC-95 (US 95), and BC-93 (US 93).

[wanderer2575]

Michigan's M-239 is a one-mile connector between I-94 and Indiana's IN-39.  (The M-39 designation was already in use.)

[TheHighwayMan3561]

ND 17/MN 317 (though Steve Riner writes this is just a coincidence based on 317's legislative route number). 317 just exists to connect MN 220 to ND 17 across the Red River.

[NWI_Irish96]

Michigan's M-239 is a one-mile connector between I-94 and Indiana's IN-39.  (The M-39 designation was already in use.)

M-217 connects to Indiana CR 17.

[SP Cook]

As to WV 527, all bridges over the Ohio that do not carry a route get a number in both Ohio and WV.  So the old route of US 52 went through town and then through Wayne County.  When 52 was rebuilt on a new course, the old road was renumbered as WV 152.  However this caused a problem because there already was an OH 152, so the section in town was numbered as WV 527.  The road changes numbers at the 5th Street exit of I-64.  This is confusing, since there was no WV 527, why not just use that number for the whole thing?

Anyway, the Hi Carpenter Bridge, better known as the St. Mary's - Newport Bridge, is WV 807, thus derived from OH 7 as well. 

And then there is WV 210, and the 3 CRs 21, and the new WV 121, all derived from US 21, which was decommisioned in WV long ago.