Maine, but only because I live about 20 miles away from it. Before we moved out here, I assumed Oregon.
This. I live less than 60 miles from Portland, Oregon, and appleciders is correct.
Maine, of course! 
I went to Univ of Maine in Orono, and lived in various places the state for almost 10 years. Grew up in CT, and am now in SC.
Having lived in both, I’m saying ME. Location is over yonder---->
And saje I went to UMO too!
Growing up in MA, I’d have said Maine; but living in the south now I’m more likely to think Oregon since it’s larger (and we’re fans of Portlandia).
Astroboy, I was there 1980-84, An.Sci. major and (dear god) Dunn Hall resident. My now husband was there too, he was my RA freshman year
I miss Maine, even the winters…
Not meaning to be contrary, but the first place to come to mind is Portland, Tennessee which I hear more about than either of those bigger cities.
If it’s down to the two in the OP, I’ll say Maine.
Just missed ya… I was '84-'88.
I’ve never been to any Portland, but I think Oregon because I’ve kept up with the Dies the Fire series.
Portland, Oregon. If I had to think of a reason why, it would probably be because I live in Portland, Oregon.
I was only dimly aware of Portland, Maine existing up until recently. I was reading Stephen King’s Night Shift and constant references to Portland made me slightly disoriented–I knew the stories were supposed to be set in Maine because, you know, Stephen King, so why are they talking about Portland, Oregon? Then I remembered that there’s a Portland in Maine too! :smack: I’m from New Jersey, and have never been to Oregon or Maine.
Portland, Maine.
From Boston, here.
Following up on my first post, I considered making a poll - Vancouver: Washington or British Columbia? But I’m pretty sure I know the results of that one. Even within Washington, people tend to assume you’re talking about BC if you just say “Vancouver”. Despite Vancouver being the state’s 5th largest city it’s still smaller than, and gets overshadowed by, Portland.
My family moved from Vancouver to Wenatchee, WA when I was in high school. On the first day of school my band teacher introduced me to the rest of the band, telling them I’d just moved from Vancouver. Two months later I was dancing with a clarinet player at a school dance, and after some very confusing questions about “when are you going back?” I realized she thought I was a foreign exchange student. All the way from British Columbia 
Sorry to revive a near dead zombie, but I didn’t see this last year.
First of all - thread bidness. Maine. I’ve lived the majority of my life in and around Portland, ME.
Secondly, I was at UMO also, for the '83 - '84 academic year (and I use the term loosely). York Hall, if what’s left of my memory serves me.
I always knew I’d be the missing link somewhere, somehow.
As a native Oregonian, I always think of the Oregon Portland when I hear the name. Now that I actually live in Portland, that reaction has only been cemented.
Maine when I lived in the East; Oregon when I lived in the West.
Exact opposite here. I live near Boston, so Maine is the default assumption. Especially since my family regularly visited one of the Casco Bay islands.
Just to be annoying – the two Portlands in Australia: on the coast, some 200 miles west of Melbourne; and, not quite 100 miles inland from Sydney.
(No, actually, I’m English: so for me, it’s the one below.)
I live in Connecticut, so I assume people are referring to Maine in the absence of contrary evidence.
Went to university in California but…
I’ll go with Portland, Maine. LL Bean and lobster rolls trumps roses and micro-brews.