The last time I walked to the top, up the cast iron spiral staircase with almost 200 steps it cost as I recall ten bucks and it's well worth the price of admission for the unencumbered views of the harbor and town and the fresh breezes blowing off the turquoise waters south of the city.
The lighthouse and the museum that is the former keeper's home make up a very pleasant grassy garden in the middle of old town. It used to be that the lighthouse was on the southern edge of the city but destructive storms persuaded the city leaders it would be more effective to have permanent structure protected from hurricanes. In those days before electricity the light must have been a beacon but nowadays I can tell you from experience that seen from the sea the lighthouse only stands out as a blinking light in an island lit up by steadily burning electrons.
I have a tendency to look up when I'm strolling around town and thus it is that from time to time I sneak a peak at the cast iron and brick tower that struggles to make itself seen in twenty-first century Key West.
Here's my full essay on visiting the Key West Lighthouse