(within Union; Hwy #66 MP 15.93-16.51, 0.58 miles)
"Over the La Grande-Baker Highway from its junction with the Old Oregon Trail Highway, I-84 and US30, south of La Grande, southerly via Hot Lake to its junction with the Medical Springs Highway in Union (common with OR237 in Union); thence southeasterly over the Medical Springs Highway via Medical Springs to its junction with the Baker-Copperfield Highway, OR86, approximately two miles northeast of Baker."
~ ODOT, Descriptions of US and Oregon Routes, July 2008
Editor's Note: I recently (January 2020) discovered a few of these old webpages that hadn't been posted to the site for some reason. So I posted them without review. Turns out there was a reason they weren't live -- these pages were clearly not ready for primetime. I don't know what I was smoking, but I made some pretty big mistakes in both my research and my reporting. I've corrected the mistakes outside of the History section, but I wanted to keep my original ramblings as a reminder to look before I leap.
OR-203 was created with the creation of the Oregon State Secondary Route system in 1935, running between US-30 in Union and OR-86 near Baker along the Medical Springs Highway #340. This route may take its namesake from the town of Medical Springs, which contains natural hot springs and pools, but it also runs along the western boundary of the Wallowa Mountains. In 1950, with the construction of a more direct US-30 between La Grande and North Powder, the northern part of that route became a northwestern extension of OR-203. (The southern part eventually became part of OR-237.) This former segment of Old Oregon Trail Highway #6 was called the La Grande-North Powder Highway #343 at this time, but the designation wouldn't last long, with the highway getting folded into the La Grande-Baker Highway #66 designation in 1968.
In 1970, OR-203 was realigned slightly south of Union, leaving OR-237 to the east at Beakman St. instead of Arch St. one block north. When the Richland interchange segment of I-80N was constructed near Baker around 1973, OR-203 was reconstructed to meet OR-86 to the east of the freeway, with the old alignment remaining to the west as a county road. However, the realignment would be short-lived; in 1980, that portion and the rest of the 4.07-mile segment along W Airport Road was turned over to Baker County. Curiously, that portion is still technically part of OR-203, despite straightline charts for the Medical Springs Highway stating otherwise.
OR-203 was created with the creation of the Oregon State Secondary Route system in 1935, running between US-30 in Union and OR-82 near Baker. This route ran (and still runs) along the western boundary of the Wallowa Mountains and through Medical Springs, which contains a natural hot springs and pools. In 1950, with the building of a more direct link of US-30 between La Grande and North Powder, the northern part of that route became a northwestern extension of OR-203 (the southern part eventually became part of OR-237).
The absolutely bizarre thing about this route is that, when I-80N was built between North Powder and Baker, it was routed down a small section of OR-203 north of Baker. So what does ODOT do? That's right, it cosigns it with I-80N to OR-86, where the designation still ends. That situation is still there today, where OR-203 runs 3.77 miles with I-84 and ends abruptly at the junction OR-86. It's a superfluous designation (which isn't even shown on I-84's straightline chart), but according to ODOT, it's there. This overdesignation should go, in my opinion; it should end at I-84.
OR-203 used to only run from Union to Baker along the western boundary of the Wallowa Mountains in northeast Oregon. Note US-30's alignment and the lack of OR-237. (©1948 Gousha)
OR-203 was extended westward to La Grande in 1950. US-30 between La Grande and North Powder and southeast of Baker will become I-80N when it's upgraded. OR-237 would come into existence the following year. (©1956 Gousha)
By 1973, I-80N was constructed through Baker. OR-203's southern terminus was moved slightly eastward. The old intersection of OR-86 and OR-203 still exists to the west of the interchange, but this map can't show it. (©1973 Gousha)
In this 2011 official state highway map, OR-203 now ends at Exit 298 on I-84 instead of at OR-86. The inset shows a part of the Baker City close-up, with W Airport Rd. not marked as a state highway. (2011 State of Oregon)
It is important to note that all map segments are copyrighted by their respective owners, and that these map segments are used for educational and historical purposes only.