Thank you for the welcomes thus far! To add a little more about myself, I am currently 30 and will be 31 in November. I enjoy driving, especially after getting a dashcam in February last year and later getting a better one in May of this year. Besides Washington, obviously, in order, I've been to Oregon, Idaho, Montana, Utah, and California.
I've been to Oregon quite a number of times, particularly from last year onward, but my first time in Oregon was a long time ago, like when I was around 20–probably even younger–for plant and tree sales. My first time being in all the other states mentioned were all after getting my first dashcam last year. Idaho and Montana were simultaneously visited in July last year when my mom and I took a trip down to Great Falls in Montana. I've been down to both of those states a few times since. The other two have only been one time so far. My mom and I went down to Salt Lake City for my birthday last year, and I visited Yreka in California back in July of this year.
In case you haven't found the answer, it has to do with Oregon's unsigned "named highways" system, which the mileposts are based off of. In this case, the Dalles-California Highway (CA to US 197, then continuing onto US 197) and Sherman Highway (US 197 to the WA border) are what US 97 use.
I did end up finding the answer, yeah. I also learned interstates are the one exception to that in Oregon, as they correctly increase from south to north or from west to east.
