Part of the Overseas Heritage Trail and almost entirely inside Curry Hammock State Park, the Grassy Key Trail is a 4.4 mile linear paved path under the power lines between Marathon and Grassy Key, hemmed in by tropical forest. At the northern end, there are expansive views of the tidal rock barrens surrounded by mangrove forest.
Location: Grassy Key, Marathon
Length: 6 mile round-trip
Lat-Lon: 24.7413, -80.9972
Fees / Permits: free
Bug factor: usually extreme, sometimes moderate
Restroom: inside Curry Hammock State Park (fee for entry)
Be very cautious of poisonwood trees along the path, as there are many in evidence. Lean your bike against signposts or benches (or use the provided bike racks) instead of against tree trunks. Put on bug spray if you plan to make any stops.
There are several options for parking to ride or walk this trail. We recommend this as a bike ride as shade is almost non-existent. Inside the state park, you should use the Grassy Key trailhead along US 1 south of the state park’s main entrance, as access to it is free.
If you are camping at the state park or enjoying the day use facilities, you can cycle out of the park and cross US 1 to meet the trail on the bay side.
If you want to start your ride farther south along US 1 to add on another 2.6 miles round-trip (total of 8.6 miles), park at the large bayside parking area on Marathon that adjoins the Overseas Heritage Trail. That route extension is shown in darker blue on the map. Unlike the rest of the route, it stays within view of US 1 for the 1.3 miles between the two trailheads.
The ride is described as we did it, northbound from the parking area that’s also used for the Curry Hammock Nature Trail, on the bay side of US 1.
0.0 > Leave the Grassy Key Trail parking area and head north along the paved path. It sits under the power lines, so there is no shade to speak of. It’s a straight line off into the distance. However, the saving grace of this trail is the screen of tropical forest between it and US 1, which helps muffle road noise and makes for a nicer view.
0.1 > A small rest stop sits next to the trail. Stop here to see the overview map and, on the back of the kiosk, information about habitats you’ll see along this route.
0.2 > Pass the turnoff for the beginning of the Curry Hammock Nature Trail at a kiosk on the left. You’ll pass a limerock road on the right, as well.
1.0 > Cross a paved road across US 1 from the main entrance to Curry Hammock State Park.
1.3 > The tidal rock barren on the bay side has been taken over by invasive species like Australian pine. The rocks are white and chalky, with some interspersed mangroves and bay cedar. Pass by a power substation with a limerock road leading to it.
2.5 > Cross Kyle Avenue. It leads back to some homes. The trail curves soon after. There is a bench and a place to walk down into the tidal rock barren for views across the mangrove-lined salt ponds. The mangroves are pretty roughed up after Hurricane Irma.
3.0 > Trail’s end is at Guava Avenue. It’s here that the Bike Route sign directs you out into traffic to cross US 1 to use the bike lane to continue north along the Overseas Heritage Trail route. Turn around here and head back to the trailhead.