A strategist for LCV said the group, which typically backs Democratic candidates that support green policies, polled the Portland area because it's the state's biggest media market — and the Portland metro area is also home to more than a third of the state's residents.
LCV endorsed Collins in her last run for reelection, and the survey — though it wasn't funded by LCV's electoral arm — is an early indication the GOP senator could again receive the green group's backing.
The poll gives her an overall 78 percent approval rating in the Portland area and indicates a large majority of Democratic, Republican and independent voters view her favorably.
Voters read positive comments about her work on environmental issues, like her opposition to cuts to Environmental Protection Agency funding, said they were more likely to support her reelection bid because of her positions on those issues.
Jeff Gohringer, spokesman for LCV, said in an email to The Hill that the poll is proof "that if you’re right on the issues that you can have a lot of support across both parties."
Maine, however, has trended Democratic on the national level in recent years, and may not be indicative of a receptiveness for environmentally-friendly policy in the GOP as a whole.
Gohringer indicated LCV would be open to backing other candidates, of both parties, that share Collins' views on environmental issues.
"As a non-partisan organization, we’re always looking for ways to help members of Congress that stand with us. Senator Collins has consistently supported common-sense environmental policies and we think she deserves a lot of credit for that. We hope others will follow her lead," he said.
The survey was conducted among 400 likely Portland-area voters from and has a margin of error of plus or minus 5 percentage points.
--This post was updated at 8:09 a.m.