Your source for that, please?The Raven is the most popular American poem ever written. It was written 180 years ago. It is also, third most popular English poem of all time after Shall I compare thee to a summer's day? by William Shakespeare, 1609 and Ozymandias by Percy Bysshe Shelley, 1818
"The Raven" may well have the record for longevity, but I think that more people are acquainted with Robert Frost's "Stopping by Woods on a Snowy Evening." Of course, "The Star Spangled Banner" beats them both, if only because somebody found that you could sing it to the tune of a popular drinking song of the day, and turned it into a a national anthem.
As for English poems, I think that Joyce Kilmer's "Trees" would be most popular. I came across that one long before "Ozymandias," probably because it was the sort of poem one would encounter in grade school.