GRASSY KEY
Homes for Sale in Marathon, FL
True comps, carrying-cost math, and listings before the portals.
Market Heat
Grassy Key is a small coastal community in Marathon, Monroe County, where the median price sits at $2,600,000 — a figure that reflects direct water access, elevated lot positions, and the relative scarcity of buildable land in the Florida Keys rather than interior square footage. At a median of roughly 1,371 square feet of living space, buyers are paying for location and lifestyle, not room count. The stock spans construction from 1938 through 2024, so condition and renovation status drive wide price variation within that single median anchor.
The market posture right now is deliberate. A median of 144 days on market signals that sellers are not moving quickly and buyers have time to underwrite carefully. A market heat score of 42 places this firmly in balanced-to-cool territory. The year-over-year median gain of 35 percent is notable, but the long-term baseline — up roughly 1,040 percent since 2012 — frames that recent jump in context: this corridor has compounded for over a decade, and short-term volatility in a thin market (four closings in the tracking window) can move the median sharply with a single transaction.
GRASSY KEY right now
🟢 Still climbing. The trailing-12-month median ($2.60M) is up 35.0% from the prior 12 months ($1.93M) and up 1040% since 2012. With about a dozen sales a year, a single closing can swing this number, so read the level and the decade, not one year's move.Momentum Research, record-level floridakeys closed sales, 12-month windows ending July 27. Confidence: Low (4 and 12 sales in the two windows).
What's unique here: the median sale price is about 3x the typical Monroe County sale ($2.60M vs $950K, trailing 12 months, floridakeys records).
Jump to: Price history & scorecard · Homes for sale · Schools · FAQ
Updated July 27, 2026 · Live data: floridakeys, refreshed twice daily · MLS facts carry their source; interpretation lines are Momentum Research · Data sources & freshness
The 60-Second Overview
GRASSY KEY market snapshot (as of July 27, 2026): the median sale price is about $2.60M, and a median 144 days on market for closed sales. The trailing-12-month median is up 35% from the prior 12 months and up 1040% since 2012, computed from record-level floridakeys closed sales (4 closings in the current window).
GRASSY KEY is a community of 294 homes in Marathon, Monroe County, built between 1938 and 2024 (median 1982.0), with a median living area of about 1,371 square feet. 38% of parcels are homesteaded, the owner-occupancy proxy in the Florida DOR assessment roll (2025 roll, public records).
Grassy Key sits within the Marathon stretch of Monroe County, where a stock of 294 homes and a median build year of 1982 reflects a mix of original Keys vernacular cottages and newer construction rebuilt or elevated after storm cycles — a physical range that makes every listing its own underwriting exercise.
Who GRASSY KEY is best for.
Best for
- A buyer with significant liquid capital who wants a Florida Keys second home and can absorb elevated insurance, flood-zone carrying costs, and a patient resale timeline.
- An investor already experienced with Keys short-term rental regulations who is underwriting yield against the current median and understands the thin comp environment.
- A buyer relocating to Monroe County full-time who has done the insurance and flood-mitigation research and wants the character of a smaller, less-commercial Keys community over a larger island hub.
Probably not for
- A buyer who needs financing confidence backed by tight comps — four closings in the tracking window will challenge appraisers and may complicate loan approval at the median price point.
- Anyone expecting a quick sale horizon; the 144-day median days on market means liquidity is limited and a fast exit strategy is not supported by current market behavior.
- A buyer stretching to reach the price point who has not fully modeled Keys-specific costs — wind and flood insurance, elevation requirements on older structures, and Monroe County permitting — which can materially affect total cost of ownership.
Price History: What Homes Here Have Actually Sold For
Median sale price over the trailing 12 months ending July 27 of each year, from record-level floridakeys closed sales. Same methodology as every appreciation figure on this page: the 2026 point ($2.60M) IS the median in the snapshot above, and the move from 2025 ($1.93M) IS the +35.0% one-year change.
Windows contain 3 to 21 sales each (4 in the current window); every figure carries its sample size, and thin markets swing on single closings. Listing data provided by Florida Keys MLS, Inc. Information is deemed reliable but is not guaranteed by the MLS to be accurate. Deemed reliable but not guaranteed.
The real cost & risk here
Before the list price, the Florida math the portals skip. These are Monroe County typicals — your exact home, flood zone, and insurance quote will vary, so verify each before you offer.
Check it for your address: look up your flood zone (FEMA) · insurance by county · true-cost calculator · Monroe County scorecard.
County typicals from Momentum’s Florida housing data (Zillow & Realtor.com aggregates, Census, FRED), updated monthly; insurance modeled. Flood zone is property-specific — always confirm via FEMA.
The GRASSY KEY buying strategy.
If we were buying in GRASSY KEY today, this is the order of operations we would run for our clients.
Underwrite the condition first. Price the roof, HVAC, and systems honestly before judging any list price; condition swings value here more than square footage alone.
Match the home to real comps. Recent sales of similar condition and lot, not the asking price, tell you what a home is worth.
Move deliberately, not desperately. Neither side has a decisive edge, so a well-prepared, fairly-priced offer wins without overpaying.
Line up financing and inspection early. A pre-approval and an inspection plan let you act fast and negotiate from evidence.
Keep an agent in your corner. The listing agent works for the seller; we represent you and prepare a hand-built valuation before any offer in GRASSY KEY.
What the numbers behind the numbers are telling you
The homestead share of roughly 38.5 percent means a majority of Grassy Key properties are held as investment, vacation, or rental assets rather than primary residences. That has direct implications for a buyer: insurance underwriting, flood zone classification, and HOA or rental licensing rules may differ from what you are accustomed to in a mainland community, and the exit market when you sell will be shaped largely by investor and second-home demand rather than move-up buyers.
With only four closings recorded in the current tracking window, this is a genuinely thin market. Comps are sparse, appraisers must reach, and a motivated seller or a distressed listing can move the recorded median in either direction with a single sale. That thinness cuts both ways: it creates negotiating opportunity for a prepared buyer and pricing risk for a seller who needs a fast close. The 144-day median days on market is the honest answer to how quickly that close typically arrives.
The location and the amenities are priced into every listing in GRASSY KEY. The deal is won or lost on condition, the comps, and the renovation math.
Momentum Buy Score.
Our proprietary 0 to 10 read across the factors that decide how a home in GRASSY KEY buys, holds, and resells. Momentum Research; not an appraisal.
Momentum Intelligence Scores are our proprietary, qualitative assessment on a 0 to 10 scale, built from the record-level market data on this page. They are a framework for comparing communities, not a guarantee of future value and not advice on a specific home; unlike an automated value estimate they do not price your home, they grade the community on evidence you can inspect. Composite is the plain average of the 4 factors (7.1). Basis: Long-Term Appreciation +1040% since 2012; Recent Direction +35.0% year-over-year; Owner Commitment 38% owner-occupied; Pricing Power 92.0% sale-to-list. Refreshed with each data update.
Why work with Momentum here
Keys transactions require more due diligence than almost any mainland Florida deal — FEMA flood maps, elevation certificates, wind mitigation reports, permit histories on older structures, and Monroe County's specific land-use rules all enter the equation before you reach price negotiation. Momentum's team underwrites the property before we underwrite the offer, so you are not discovering material issues at inspection. If the numbers or the condition do not support the ask, we will tell you plainly and walk away with you.
GRASSY KEY in 15 seconds.
HOA, CDD & Fees
- Mandatory HOA — confirm current dues
- Any club/amenity membership is billed separately
Confirm the current HOA dues, exactly what they cover, and any CDD bond or special assessment for a specific address before you offer.
Tools for a GRASSY KEY buy.
Free calculators to pressure-test the real cost before you tour.
Selling here is won on condition and pricing to real comps, not an automated estimate. The right number comes from closed GRASSY KEY sales matched to your home.
Price it to the comps and condition, not an automated estimate.
If you are thinking about selling in GRASSY KEY, the right list price comes from recent comparable sales matched to your home's condition and location, not an automated estimate.
What is your GRASSY KEY home worth?
Get a no-obligation home value based on real comparable sales in GRASSY KEY, not an automated guess. Tell us about your home and we will personally prepare your numbers and a pricing strategy. No obligation, no spam.
See homes for sale in GRASSY KEY on the map →
Frequently Asked Questions
What is the median home price in GRASSY KEY?
How long do homes in GRASSY KEY take to sell?
How many homes are in GRASSY KEY?
What share of GRASSY KEY is owner-occupied?
When were the homes in GRASSY KEY built?
Do cash buyers compete in GRASSY KEY?
Have GRASSY KEY home prices gone up?
Who is the best real estate agent for GRASSY KEY?
How do I find a top Marathon real estate agent who knows GRASSY KEY?
Can Momentum Realty connect me with an agent for GRASSY KEY?
Should you buy in GRASSY KEY?
An honest fit check. We will tell you when it is not your community.
Data sources & freshness
| Community market stats | floridakeys closed sales, 12-month windows ending July 27, 2026 |
| Housing stock & ownership | Florida DOR 2025 assessment roll (street-list match (17 streets, ZIP 33050/33051)) |
| Historical depth | Closed-sale records back to 2005 (217 transactions analyzed) |
Verify the primary sources yourself: Florida DOR · U.S. Census · FEMA flood maps · Citizens Property Insurance.
Momentum Research figures are our own analysis of floridakeys records; MLS data is deemed reliable but not guaranteed. Methodology: how Momentum market scores are computed. Market metrics describe homes for sale and recent sales, not residents.
Own a home here?
You just read the data. Now see what your home is worth.
The numbers on this page move markets in the aggregate. The number that matters to you is what a buyer pays for your address. Momentum sells for 1.25% above the floridakeys member average and 8 days faster, and we’ll price yours against live your area comps.
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More Marathon & The Florida Keys & Monroe County guides
Compare before you commit - every guide covers pricing, HOA/CDD, insurance posture, and fit. Browse all of The Florida Keys & Monroe County or the full Neighborhood Finder.