Columbus, GA
It is an estimated 4 hours and 39 minutes of driving time according to MapQuest.
No
A one hour drive south of Portland will take you to Salem, Oregon-- the third largest city in Oregon.
There are no major cities along 45° S latitude. The closest cities are the fjord city of Puerto Aisén in Chile (45°24′S, 72°41′W) and the Argentine town of Sarmiento (45°36′S, 69°5′W).