The neighborhood known as Old Naples Florida does not have a precise definition, but I'll give it a shot here.
I always think of the northwestern corner of Old Naples to be the Naples Beach Hotel and Golf Club.
This was one of the earliest hotels in modern Naples, and is still a great place to stay. The locals love it for drinks at sunset. It is at the Gulf end of South Golf Drive (also known as 8th Avenue North.
One of the original landmarks of Old Naples is Palm Cottage. Built in 1895, it is on the National Register of Historic Places and is near the Naples Pier.
Naples zoning does not allow any condos on the ocean south of the hotel, so there are only single family homes on the beach all the way down to the southern limit of Old Naples and beyond to Gordon Pass and Keewaydin Island.
Some of these homes are bigger than the entire building for many condominiums.
Old Naples is a charming combination of old beach cottages and mansions resting peacefully among hundreds of tall coconut palms and banyan trees.
Some of the new mansions stand beside old houses dating back to the early 20th century.
Every avenue, from Golf Drive on the north to 14th Avenue on the south ends at the Gulf. These avenues each have little city parks with benches and are favorite spots for locals to watch the sunset.
The neighborhoods south of that, Aqualane Shores and Port Royal, are beautiful upscale communities that were dredged up out of the mangroves in the 1950's and are therefore not "old" by Old Naples standards.
The Old Naples I am describing is all west of U.S.-41 until the highway bends east and heads over to Miami as the famous Tamiami Trail.
Then for the short section of US-41 that heads west before the bridge over the Gordon River, everything south of 41 and west of the Gordon River is Old Naples.
Tin City, a restored fishing village, is a local shopping venue on Gordon River that is in Old Naples.
Some people also refer to "Olde Naples Florida" (notice the e added to old), and that is generally the area around the Naples Pier and Third Street South.
I lived in Old Naples from 2004 to 2010, and it will always rank as one of the nicest places I've ever lived. My small condo was two blocks from the shops and restaurants of Fifth Avenue South, and six blocks from the Third Street South historic district.
For great places to stay and eat in Old Naples, see our page on Naples.