There once was an old man of Lyme
Who married three wives at a time,
When asked, "Why a third?"
He replied, " One s absurd!
And bigamy, sir, is a crime."
OK so maybe it's not really ABOUT Lyme Regis, but once you've read this, you will never think of the town without thinking of this poem. It is part of the cultural geography of Lyme, whether the citizens of Lyme like it or not.
Dorset turns out to be very well-mapped poetically. The Poetry Atlas has plenty of poems about Dorset places.