More historic than 30% of U.S. towns · #159 of 638 in Florida. What drives it
Most of Key Biscayne was built recently: 0.4% of its homes predate 1940 and the median home dates from 1977. Below: 5 old photos and papers, maps from 1947 on, and the census since 2000.
Founding year: the first Key Biscayne post office (Blevins & Helbock, CC0). Wikidata: 1991.The full story ↓
History grade
What drives Key Biscayne’s History grade
On its age, its old homes and the National Register, Key Biscayne is more historic than 30% of U.S. towns, #159 of 638 in Florida. Its age holds the grade up; its share of homes from before 1940 pulls it down.
C
HistoryA character grade: shown, never part of Key Biscayne’s overall grade.
Few Florida towns list much on the Register (a typical Florida town has 0.0 per 10,000 residents, the U.S. 2.4), so Key Biscayne’s 0.0 sits below most of its state (33% of Florida towns have fewer) while its 0 listings outnumber those of 23% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from D to B−. The pre-1940 share (±0.7 points) is firm at this size. The founding year is the first post office, not a stated founding date; Wikidata gives 1991.
Founding year: the first post office (other dates in Quick answers). Homes: Census ACS 2020–24. National Register: National Park Service, May 2026 list; each listing counted once (boundary changes and added documentation belong to their listing), and a historic district counts its contributing buildings. How TownRatings grades history →
What stands out about Key Biscayne’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
While there had been earlier plans to develop a town on Key Biscayne, the opening of the 4-mile-long (6.4 km) Rickenbacker Causeway from Miami to Virginia Key and on to Key Biscayne in 1947 opened the island up to large-scale residential development. The northern two-thirds of the island had operated as the largest coconut plantation in the continental United States during the first half of the 20th century.
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
The Key Biscayne post office opened in 1839, the earliest record of the town by name (U.S. post office records). Wikidata gives 1991.
How does Key Biscayne rank for history?
Key Biscayne is more historic than 30% of U.S. towns, #159 of 638 in Florida. The History grade combines the town’s founding era, the share of homes built before 1940 and its National Register listings. It’s a character grade, so it isn’t part of the overall grade. How it works.
How old are the homes in Key Biscayne?
0.4% of Key Biscayne’s homes were built before 1940 (Census estimate), against a typical 0.6% for a Florida town; the median home was built in 1977.
Founding dates: Wikidata, Wikipedia, the U.S. post office records of Blevins & Helbock (CC0) and the Census. Homes by year built: Census ACS 2020–24. National Register of Historic Places: National Park Service (list of May 22, 2026). Old photos, postcards and papers: Wikimedia Commons, the Library of Congress and other public archives, credited on each item’s page. Maps: U.S. Geological Survey historical topographic maps (via Esri) and Sanborn fire-insurance maps (Library of Congress). History text and census tables: Wikipedia (CC BY-SA 4.0). Places that used to be: USGS Geographic Names Information System (2021).
From Wikimedia Commons (4), the Library of Congress (1), Wikidata (1), Wikipedia, Wikidata and Wikipedia for famous people, U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia), the US Post Offices dataset (Blevins & Helbock) and the USGS Geographic Names Information System. Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
1900
