Quick Definition
Marathon is a city of approximately 8,300 permanent residents occupying the middle section of the Florida Keys from Mile Marker 60 to Mile Marker 35 — the geographic and logistical heart of the 125-mile Overseas Highway chain. The city spans Vaca Key (the main island), Boot Key, Knight's Key, and several smaller islands. Marathon's defining landmark is the Seven Mile Bridge (completed 1982, 35,716 feet long), connecting Marathon to the Lower Keys at MM 40–47 — one of the longest segmental bridges ever built and, at its midpoint, one of the most dramatic views in Florida. The adjacent Old Seven Mile Bridge (1912, originally Henry Flagler's Florida East Coast Railway extension) is now a 2.2-mile pedestrian and bicycle path offering 360-degree ocean views. Crane Point Museum and Nature Center (63 acres, MM 50) preserves the largest undisturbed tract of tropical hardwood hammock forest in the Keys, with an 18,000-year-old coral reef and Calusa and Bahamian settler history. Marathon has the only full-service hospital in the Keys (Fishermen's Hospital), a full-size grocery store (Publix MM 50), and Home Depot (MM 53) — making it the supply hub for the entire Keys chain. Explore the wider region at Florida Keys RV parks.
TL;DR
- Population 8,300; MM 35–60 — geographic center of the Florida Keys
- Seven Mile Bridge (1982, 35,716 feet) — one of the longest segmental bridges ever built, connecting Marathon to the Lower Keys
- Old Seven Mile Bridge (1912): 2.2-mile pedestrian/bike path with 360-degree ocean views
- Crane Point Museum (63 acres, MM 50): largest undisturbed tropical hardwood hammock in the Keys, 18,000-year-old coral reef on site
- Only full-service hospital in the Keys (Fishermen's Hospital) + Publix MM 50 + Home Depot MM 53
- Bahia Honda State Park (best beach in Keys, full hookup $28–43/night) is 13 miles south at MM 37
Marathon RV Access Zones: Boot Key, Gulf Side & Seven Mile Bridge Corridor
Vaca Key / Boot Key Harbor (Central Marathon). Boot Key Harbor is one of the most popular hurricane-hole anchorages in the Keys, surrounded by Boot Key and Vaca Key. The City of Marathon marina at Boot Key Harbor offers mooring balls for liveaboards but limited RV access. The main commercial stretch of Marathon (MM 47–53) runs along US-1 through Vaca Key with all major services: Publix (MM 50), Winn-Dixie (MM 49), Home Depot (MM 53), Fishermen's Hospital (MM 48.5), and a full selection of restaurants. RV parks in this corridor are within 5–10 minutes of all Marathon services.
Gulf Side / Florida Bay (North). The Gulf (north) side of Marathon faces Florida Bay's shallow, calm waters — ideal for kayaking, flat-bottom boating, and wade fishing for tarpon and bonefish. Gulf-side parks offer sunset views over Florida Bay rather than Atlantic sunrise. The waters are generally calmer than the Atlantic side, making them popular for kayak launchings. Gulf-side parks in Marathon typically sit at MM 48–55.
Knight's Key / Seven Mile Bridge (South Marathon, MM 40–47). Knight's Key is the southernmost point of Marathon and the northern terminus of the Seven Mile Bridge. The Old Seven Mile Bridge pedestrian path begins from the Knight's Key Blvd parking area (free, off US-1). Parks in this zone are closest to the bridge experience — walk or bicycle the old bridge at sunrise before other visitors arrive. Pigeon Key (36 acres under the old bridge, MM 47) is accessible by ferry from the Knight's Key park or by bicycle across the bridge. The key served as the construction workers' camp during the 1905–1912 railroad building and houses 5 original buildings now serving as a museum ($15/adult).
Grassy Key (MM 57–60, East Marathon). Grassy Key is immediately east of Marathon proper and hosts Dolphin Research Center (MM 59, established 1984, non-profit cetacean research facility with public dolphin swim programs at $210–650/person). The key also has the Curry Hammock State Park (MM 56.5), which protects 1,000+ acres of mangrove, rockland hammock, and seagrass environments and offers RV camping. Rates at Curry Hammock run $28–43/night. Eastern Grassy Key private parks run $70–100/night. This zone provides quiet, nature-focused camping within 5–10 minutes of full Marathon services. Travelers heading north will find the Upper Keys fishing and reef scene at Islamorada RV parks, 27 miles away.
What to Do in Marathon by RV: Five Must-Experience Activities
Old Seven Mile Bridge Walk/Bike (2.2 Miles, Free). The original Seven Mile Bridge, built 1912 as part of Henry Flagler's Florida East Coast Railway extension, was converted to road use in 1938 and decommissioned in 1982 when the new bridge opened. The 2.2-mile pedestrian section beginning at Knight's Key (the full bridge's 7-mile length is not entirely open; 2.2 miles is the walkable portion) offers 360-degree views of the Atlantic and Gulf meeting at the bridge's midpoint. Sunrise on the old bridge — when the sky turns pink and orange over the Atlantic and pelicans fish the pilings — is one of the genuine free spectacles in the Keys. Arrive at dawn; the bridge empties by 7am on weekdays, giving photographers unobstructed access to the railing.
Pigeon Key Historic Site (MM 47, Accessible by Ferry or Bike). Pigeon Key (36 acres) housed the construction workers who built Henry Flagler's railroad across the Keys between 1905 and 1912 — one of the most ambitious engineering feats of the early 20th century. The project killed 135 workers in the Labor Day Hurricane of 1935 and ultimately succeeded where skeptics said it was physically impossible. Five original 1912 buildings remain on the key and have been restored as a museum. The Pigeon Key Foundation operates $15/adult tours that include historical interpretation of the railroad era, the hurricane disaster, and the key's subsequent life as a research station. Ferry from the Knight's Key visitor center departs hourly; bicycling across the 2.2-mile old bridge is the more satisfying approach.
Crane Point Museum and Nature Center (63 Acres, MM 50). Crane Point is Marathon's most underrated attraction and one of the most significant natural sites in the Keys. The 63-acre preserve contains: the largest undisturbed tract of tropical hardwood hammock forest in the Keys; an 18,000-year-old coral reef exposed above ground (one of few such accessible fossil reefs in Florida); Calusa Indian artifact sites from 700+ years of habitation; and restored 19th-century Bahamian settler buildings. The 1.5-mile trail network runs through the hammock forest — look for white-crowned pigeons and mangrove cuckoos. Admission $15/adult. Hours: Mon–Sat 9am–5pm, Sun noon–5pm. The Marathon Wild Bird Center (adjacent, free) rehabilitates injured Keys birds; great blue herons and pelicans are frequently seen at close range.
Dolphin Research Center (Grassy Key, MM 59). The Dolphin Research Center (established 1984) is a legitimate non-profit research facility that operates public education programs alongside its scientific work. Dolphin Encounter ($210/person, 30 minutes in-water) and Dolphin Splash ($100/person, dock interaction only) are the signature experiences — advance booking is required weeks ahead. Unlike commercial dolphin shows, DRC emphasizes natural behavior and consent-based interaction. The facility's dolphins are born there or long-term rescues; they're not imported show animals. Educational tours of the facility ($30/adult) run throughout the day for visitors who prefer observation.
Reef Snorkeling and Scuba (Atlantic Side, Multiple Operators). Marathon sits atop one of the most accessible stretches of the Florida Keys reef — the third-largest coral barrier reef in the world. Half-day snorkel trips ($45–65/person, 3–4 hours) depart from several Marathon marinas and target sites like Sombrero Reef (MM 50, Atlantic side) — a 36-foot-tall lighthouse reef with extensive coral structure, abundant fish, sea turtles, and frequent nurse shark sightings. Full-day dive boats ($85–120/person) reach deeper reef zones. Visibility typically exceeds 50–80 feet. Equipment rental and instruction available through all operators. The Florida RV parks guide covers reef-adjacent camping up and down the state for travelers expanding beyond the Keys.
Practical Tips for RVing in Marathon
Marathon Is the Keys' Supply Hub — Stock Up Here. If you're driving further south to Big Pine Key, Key West, or Bahia Honda, Marathon is your last opportunity to buy groceries, hardware supplies, or medical supplies before prices spike and selection shrinks. Publix (MM 50) is the largest grocery in the Keys; Winn-Dixie (MM 49) is an alternative. Home Depot (MM 53) carries basic RV supplies and hardware. Fishermen's Hospital (MM 48.5) is the only full-service hospital between Homestead (90 miles north) and Key West (50 miles south) — important to know for genuine emergencies.
Curry Hammock State Park Reservations. Curry Hammock (MM 56.5, 1,000+ acres) offers full-hookup RV sites at $28–43/night — among the best value in the middle Keys. Book on reserveamerica.com as far as 11 months in advance; peak season (December–March) sites fill fast. The park's kayak trail through mangroves and seagrass is accessible from a launch inside the park (free for campers). Wind conditions on the Atlantic side can be challenging — paddle the Gulf-side mangrove trail for calmer water.
Keys Bridge Height and Lane Width. The Seven Mile Bridge (new, 1982) has no height restrictions for standard RVs. The two-lane road narrows slightly at bridge guardrails — wide rigs (over 8.5 feet) should drive confidently in the center of their lane without drifting toward the rail. The Old Seven Mile Bridge is open to foot and bicycle traffic only. Do NOT attempt to drive across the old bridge — it's structurally maintained only for pedestrian loads.
Fuel Pricing in Marathon. Fuel in Marathon runs $0.30–0.50/gallon above mainland prices but lower than Key West. Marathon is the last major fuel stop before Key West — fill up here rather than paying Key West fuel surcharges. Marathon has multiple fuel stations on US-1 near MM 48–52.
Summer Heat and AC Demand. Marathon's subtropical latitude means summer temperatures reach 90–95°F with 80%+ humidity June–September. Shore power at full-hookup sites is essential for air conditioning. Confirm amp service (30A vs. 50A) before booking; large Class A and Class C rigs with multiple ACs require 50A service. Run errands and outdoor activities before 10am and after 5pm during summer. Upper Keys parks offer slightly cooler conditions — see Key Largo RV parks if summer heat is a concern for your dates.
Cost Math: Marathon RV vs. Key West Hotel (3 Nights, Peak Season)
| Accommodation | Nightly Rate | 3-Night Total |
|---|---|---|
| Curry Hammock State Park (full hookup) | $35 | $105 |
| Grassy Key private RV park (full hookup) | $85 | $255 |
| Marathon area mid-range motel | $160 | $480 |
| Key West budget hotel (off Duval) | $280 | $840 |
Marathon's strategic position — 50 miles from Key West (60–75 minutes), adjacent to Bahia Honda (13 miles), and central to the whole Keys chain — makes it a legitimate budget hub. A week at Curry Hammock ($35/night) costs $245 versus $1,960 for a Key West hotel, saving $1,715. The drive to Key West is real, but the savings are decisive.
Marathon RV Parks: At a Glance
| Park Name | Location | Full Hookups | Pull-Thru | Nightly Rate | Pets | Wi-Fi |
|---|---|---|---|---|---|---|
| Curry Hammock State Park MM 56.5 | Yes | No | $28–43 | Yes | No | |
| Grassy Key RV Park | MM 58.5 | Yes | Yes | $70–100 | Yes | Yes |
| Fiesta Key RV Resort | MM 70 | Yes | Yes | $80–130 | Yes | Yes |
| Marathon RV Park | MM 49.5 | Yes | Yes | $65–95 | Yes | Yes |
| Long Key State Park MM 67.5 | Yes | No | $28–43 | Yes | No | |
| Bahia Honda State Park MM 37 | Yes | No | $28–43 | Yes | No | |
| Big Pine Key Fishing Lodge | MM 33 | Yes | Yes | $65–95 | Yes | Yes |
| Sunshine Key RV Resort | MM 39 | Yes | Yes | $70–110 | Yes | Yes |
Frequently Asked Questions
What is Marathon, FL known for? Marathon is the geographic and logistical center of the Florida Keys — home to the Seven Mile Bridge, the only full-service hospital in the Keys, the largest grocery store in the chain (Publix MM 50), and the supply infrastructure the whole archipelago depends on. It's also the base for Middle Keys reef snorkeling, Pigeon Key historic tours, and Crane Point's tropical hardwood hammock. For RV travelers driving the full Keys chain, Marathon is the natural overnight stop midway.
How long is the Seven Mile Bridge? The new Seven Mile Bridge (completed 1982) is 35,716 feet long — just over 6.7 miles. It replaced Henry Flagler's original railroad bridge (1912, now a 2.2-mile pedestrian path). The bridge spans from Knight's Key in Marathon to Little Duck Key in the Lower Keys. At its midpoint, the Atlantic Ocean (east) and Gulf of Mexico (west) are simultaneously visible in both directions.
What is Pigeon Key? Pigeon Key (36 acres, MM 47) is the former construction workers' camp for Henry Flagler's Florida East Coast Railway extension across the Keys (built 1905–1912). Five original 1912 structures survive and have been restored. The Pigeon Key Foundation operates guided tours ($15/adult) covering the railroad's engineering history, the Labor Day Hurricane of 1935 that killed 135 workers, and the key's subsequent research station use. Access by ferry from Knight's Key or bicycle across the old Seven Mile Bridge.
What is Crane Point Museum? Crane Point Museum and Nature Center (63 acres, MM 50) is a protected preserve containing the largest undisturbed tropical hardwood hammock in the Florida Keys, an 18,000-year-old exposed coral reef, Calusa Indian artifact sites, and restored Bahamian settler buildings. It's Marathon's most underrated attraction. Admission $15/adult. Trails wind through hammock forest; the Marathon Wild Bird Center (adjacent) rehabilitates injured Keys birds. Hours: Mon–Sat 9am–5pm, Sun noon–5pm.
Is Bahia Honda near Marathon? Bahia Honda State Park (MM 37) is 13 miles south of Marathon via US-1 — approximately 15–20 minutes. It's the most popular beach in the Keys and one of the top-rated beaches in the eastern US. Full-hookup RV sites cost $28–43/night. Book 11 months ahead on reserveamerica.com. Marathon-area RV travelers regularly day-trip to Bahia Honda beach while camping at Marathon parks (better availability and often lower rates than Bahia Honda itself).
What is Curry Hammock State Park? Curry Hammock State Park (MM 56.5, 1,000+ acres) protects mangrove, rockland hammock, and seagrass habitat in the Middle Keys. Full-hookup RV sites cost $28–43/night — excellent value for the Keys. The park's kayak trail through mangroves is accessible for campers at no extra charge. Book on reserveamerica.com for peak season (December–March); sites fill quickly. The hammock's nesting area for migratory birds peaks in May–June.
Can I walk or bike the Seven Mile Bridge? Yes, but only the Old Seven Mile Bridge (1912 original). A 2.2-mile section from Knight's Key opens to pedestrians and cyclists — the full 7-mile span is not entirely walkable. The walkable section offers 360-degree views of both the Atlantic and Gulf. Parking at Knight's Key Blvd (free, off US-1 at MM 47) provides trailhead access. Best time: sunrise weekdays, before other visitors arrive.
What reef is near Marathon? Sombrero Reef (MM 50, Atlantic side, 5 miles offshore) is the signature Marathon dive site — a 36-foot lighthouse marks the reef, with coral formations, sea turtles, nurse sharks, and abundant fish life in 10–30 foot depth. Multiple Marathon operators run half-day snorkel tours ($45–65/person) and full-day scuba trips ($85–120/person) to Sombrero and nearby sites. Visibility typically 50–80 feet year-round.
How far is Marathon from Key West? Marathon to Key West is approximately 50 miles via US-1 — 60–75 minutes under ideal conditions, 90+ minutes with peak season traffic. Many Marathon-based RV travelers day-trip to Key West mid-week (Tuesday–Thursday) when traffic is lighter, spending the morning in Old Town and returning by early afternoon before rush-hour congestion builds on the Overseas Highway.
What's the best RV park in Marathon? Curry Hammock State Park (MM 56.5) offers the best value: full hookups at $28–43/night in a natural 1,000-acre setting with kayak access. For amenities (pool, Wi-Fi, laundry), Grassy Key RV Park (MM 58.5) at $70–100/night is the leading private option. Fiesta Key RV Resort (MM 70) sits on a small island of its own between Long Key and Grassy Key and offers direct Florida Bay water access.
Thinking About Selling Your RV Park in Marathon?
Marathon's position as the supply hub of the Florida Keys makes RV parks here uniquely defensible assets. Travelers staging for Key West or Bahia Honda need a central base; Marathon parks fill that role year after year. The Dolphin Research Center, Crane Point, and Sombrero Reef draw repeat visitors who return to the same parks season after season — occupancy stability that institutional buyers price favorably.
Monroe County's Rate of Growth Ordinance (ROGO) blocks new park development throughout the Keys — Marathon included. Existing park operators hold scarcity value that isn't available anywhere else in Florida camping. Cap rates in the Middle Keys run 8–11%.
Contact Jenna Reed at jenna@rv-parks.org or visit /sell to discuss your property's position in this market.