Long state highway in one state ties into very short highway in another

[TheHighwayMan3561]

The longest state highway in Wisconsin, WIS 35 becomes ILL 35, the shortest state highway in Illinois.

The longest state highway in Minnesota, MN 1 becomes ND 54, a 2 1/2 mile route between the Red River and I-29.

[Scott5114]

Montana 200 is a 900-mile-long highway, the longest state highway in the US. It connects to ID-200, which is a comparatively paltry 33 miles. Maybe not so short in absolute terms, but in terms of percentage it would be hard to beat.

[Mapmikey]

OH 32 which crosses the entirety of Ohio becomes WV 618 which runs only a few miles through Parkersburg WV

PA 18 which begins at Lake Erie becomes WV 69 which runs only a few miles to US 250

[Max Rockatansky]

NV 88 (7.86 miles) versus CA 88 (122 miles).

[hotdogPi]

VT 26...

[SkyPesos]

Not as dramatic as some other examples, but there is OH 2 (227 miles) turning into the northern segment of IN 37 (14 miles) past its western terminus.

[NWI_Irish96]

153 mi IN 28 becomes 8 mi IL 119
121 mil IN 39 becomes 1 mi MI 239

[skluth]

IA 27, aka the Avenue of the Saints, runs N/S through Iowa but only runs a few miles as MO 27 before ending at US 61.

[MATraveler128]

There used to be KY 80 becoming MO 80, which is 6 miles, but the connection has since been discontinued. It does become VA 80, which is 67 miles compared to the 483 miles in Kentucky.

[Bruce]

US 395 (1,305 miles) becomes BC Highway 395 at the Canadian border, which ends a mere 2.5 miles later.

Another short one on the Canadian border: BC Highway 41 (0.8 mi) ties into WA 21 (191 mi).

[Rothman]

US 395 (1,305 miles) becomes BC Highway 395 at the Canadian border, which ends a mere 2.5 miles later.

Another short one on the Canadian border: BC Highway 41 (0.8 mi) ties into WA 21 (191 mi).

I-95, NB 95...

[GaryA]

CA 62 (151 miles) becomes "TRUCK AZ 95", a 0.85 mile connector to AZ 95 in Parker.

[tmthyvs]

Interstate 29 (750 miles) used to become MB 29 (0.3 miles) at the Emerson/Pembina border crossing.

[LilianaUwU]

QC 132, at a thousand miles, connects with NY 970T at its west end. It's a reference route in NY, though, so I don't know if it counts.

[Mark68]

US 395 in NV (88.62 miles), which lies between two sections in CA totaling 556.91 miles.

[cwf1701]

Indiana 39 (179 miles north section) becoming M-239 (1.1 miles) to end at I-94 just after crossing the state line.

[jp the roadgeek]

RI 15 becomes (unsigned) MA 15, which is 0.23 miles
MA/NH 119 becoming the 0.08 mi. VT 119
The 122.45 NY 55 becomes the 2.64 mile CT 55
PA 491 becoming the 0.66 mile DE 491
RI 78 becoming the 0.43 mile CT 78 (even less than that if you subtract the loop ramp)

And a double: MA 114A becoming the 0.1 mile segment of RI 114A on its southern end, and the 0.3 mile segment on its northern end.

[MATraveler128]

The eastern US 2 enters New York for 0.9 miles.

PA 413 enters New Jersey for 0.7 miles.

NH 108 enters Massachusetts for 0.9 miles.

[Big John]

MN 23 - 343 miles in MN and 1/2 mile in WI.

[ilpt4u]

IN 62 stretchs across Southern Indiana, from meeting US 50 near Dillsboro/not too far from I-275 and the Ohio River and Cincinnati, and comes all the way west and south, thru New Albany, then Evansville and Mount Vernon, to cross the Wabash River into Illinois, and becomes IL 141 - clocking in at 204 miles (per wikipedia)

IL 141 is all of 18 miles from the Wabash to US 45

[wanderer2575]

IN-15 (95 miles) enters Michigan and becomes M-103 (3 miles).

[JREwing78]

Can't forget US-131.

IN: 0.64 miles

MI: 269.32 miles

[Takumi]

NC/VA 87: 239 miles in NC, 4 in VA.

[Hobart]

Montana 200 is a 900-mile-long highway, the longest state highway in the US. It connects to ID-200, which is a comparatively paltry 33 miles. Maybe not so short in absolute terms, but in terms of percentage it would be hard to beat.

This gets even more dramatic if you consider that Montana 200 is connected to North Dakota 200, which spans the entire state, and Minnesota 200, which almost spans its entire state.

Effectively, Idaho gets a 2.43% slice of a four-state, 1,356 mile Highway 200 to its name. I'd say that's even harder to beat.

[froggie]

MA/NH 119 becoming the 0.08 mi. VT 119

Which will change in a few years when the new bridge downstream is finished.  Not sure offhand how much, though.

Montana 200 is a 900-mile-long highway, the longest state highway in the US. It connects to ID-200, which is a comparatively paltry 33 miles. Maybe not so short in absolute terms, but in terms of percentage it would be hard to beat.

This gets even more dramatic if you consider that Montana 200 is connected to North Dakota 200, which spans the entire state, and Minnesota 200, which almost spans its entire state.

Effectively, Idaho gets a 2.43% slice of a four-state, 1,356 mile Highway 200 to its name. I'd say that's even harder to beat.

Vermont has 2 examples already mentioned that beat it...

VT/NH/ME 26:   126.77 miles.  53 feet in Vermont.  0.008%
VT/NH/MA 119:  75.67 miles.  0.08mi in Vermont.  0.1%