This is a Google Map of the course from Sleepy Hollow High School to John’s Field and back (with mileage of just over 8 miles).
Google Satellite I: The OCA North requires a broad view. It essentially runs from the bottom center (a close-up is in the next shot below) across Route 117 and to the left, ending just to the left and below the golf course, which is the Sleepy Hollow Country Club. You continue toward Cortlandt after crossing Route 9. The rest of the park area you see is the Rockefeller Estate. You can see why one might fear getting lost there.
Google Satellite II: The Sleepy Hollow High School parking lot is to the left of the track. The OCA is the brown area just up and to the left of the parking lot.
You can see the early stretch here; the OCA is the white line in the center to the left and the diagonal line above that. The building below is right at the base of that diagonal stretch. There are several spots where the Rockefeller Park is easily accessible to your right, and you ultimately cross a bridge over Route 117. The OCA veers to the west just across the bridge; after you cross, you turn left for the OCA and right for the Rockefeller. It’s well-marked with the familiar green sign-post for the OCA.
This is a pretty straight-forward running, with no road crossings. It’s easy to follow. As one frame of reference, “Sleepy Hollow” used to be “North Tarrytown.” This segment of the OCA ends in Scarborough just to the west of Broadway/Rte 9 (Albany Post Road here). When you reach this road, you may be tempted to turn right to Route 9. Resist. Route 9 has no shoulder, two narrow lanes, and a 40 MPH speed limit. Trying that could qualify one for a Darwin Award. Here is a map of the northern portion.
Instead, turn left down the hill and follow River Road around. It is something of a switch-back that takes you down, but gradually. Right before you head down to the Scarborough station, take the right up Scarborough Station Road. This is a hill, at the top of which you will see a church steeple. To continue on the trail, cross Route 9 and turn left for a brief stretch to the next light. Turn right and you see the OCA a short distance ahead. It crosses and you go to the left. I’ve not run this part, although I have driven by it.
There is a very nice diversion shortly before the trail ends and right after you’ve crossed the bridge across Rte 9 (which is the second bridge you cross). You can see it on this Rockefeller Park Map, in the area around “John’s Field.” Note, this is not part of the OCA and it does not allow bikes. You take a hairpin turn to your left and then the trail switch-backs down. Just follow it to the right (you cross 5 wooden bridges over a creek), and it takes you around a beautiful open field that overlooks the Hudson. Work around counter-clockwise and up a switchback hill and through an opening in the trees to a promenade of grander days, on large cobblestones (the pictures above). This is “Rockwood Hall”on the map. You then continue around to either the trail you came in on or to a road you must go down to pick up the trail at the bottom of the switch-backed hill.
You can also enter the system here, at a parking lot at the end of Route 117, past Route 9. But be warned, if you finish here, the last few hundred meters of your run will be up that pretty steep switchback, which is in the picture to the right.
Also, you can ride bikes on the OCA. The OCA North (because it goes away from the Aqueduct itself for stretches) is not especially flat and straight. On off-peak hours (and all week-end, you can bring bikes on Metro-North trains, although you should have a pass. You cannot ride in the Rockefeller Park. (By Public)
This Google Satellite shot shows the Sleepy Hollow High School parking lot (it’s long and narrow). Convert to the map view for directions. You can enter it from Route 9 or from Route 448. You can also enter it from a small parking lot at the end of Route 117, which is the tenacle-like stretch just north of Phelps Memorial Hospital; you enter at the southeast corner of John’s Field.
Rockefeller State Park is actually fairly easy to get to using Metro North, but for it to be worthwhile plan on a 15-20 miler as opposed to a 10. It’s about 1.2 miles from the train station to the trail.
You can take the Hudson Line to the Tarrytown, NY stop, a 38 min train ride from Grand Central Terminal. Then, run up the hill, east, about 1 mile, to North Broadway, which is the main drag through Tarrytown (and same Broadway that’s in Manhattan & the Bronx). MetroNorth Schedule
Head north on Broadway until you get to an intersection of Broadway (Rte 9) and 448. On the SE corner of this intersection is the Horseman Diner (a good place to eat after your run). Head east on Rte 448. In about 150 meters you will come to an entrace to a parking lot on your right. This is the Sleepy Hollow HS parking lot.
On your left, across Rte. 448, is a dirt trail, about 40 feet wide, called the Old Croton Aqueduct. You can run north on the “OCA” about 2 miles and enter the trail system for the Rockefellers.
I would encourage all novice visitors to the Park to carry a map of the trail system for it can be very confusing. You can obtain a map here: