If my memory is correct, the last Republican Congressman there was not considered a conservative.
Wendell Wyatt was a moderate (a little more liberal than we’d like, but nowhere in the range of the moonbat Pete McCloskey). John Dellenback, a Republican who represented the 4th was more liberal. Ironically, the “Conservative” in the delegation was neither of the 2 Republicans, but was Portland’s Democrat Congresswoman Edith Green. She was elected in one of the two liberal sweeps (1954 & 1956, which turned OR from a GOP-leaning state federally to Democrat) and started out a reliable leftist but moved rightward throughout her time in the House. She left the House in 1974 along with Wyatt (Dellenback was defeated) and promptly endorsed Gerald Ford for President. If she were in the House today, she’d have no equal amongst the Dems on the right (at the time, she had quite a bit of company).
At the time, the GOP’s loss in the 1st was considered nothing short of shocking because we had an excellent young candidate expected to keep the seat, Diarmuid O’Scannlain. Pres. Reagan eventually appointed O’Scannlain to the federal bench a dozen years later.
Maybe you’re thinking of the OR-04 (where GOP Congressman Bunn was a bit of a squish).