The Mashomack Preserve 
Route 114, Shelter Island
Often referred to as "the jewel of the Peconic," the Mashomack Preserve covers one-third of Shelter Island with over 2,000 acres of marshes, creeks, mature oak woodlands and fields. The preserve is filled with great Fall colors right now. Entry is free, but donations are also accepted.

Quogue Wildlife Refuge 
3 Old Country Road, Quogue
The Quogue Wildlife Refuge is nearly 80 years old and boasts 305 acres of unique natural habitats, such as Pine Barrens, bogs, wetlands and a tidal estuary. The Refuge is open 365 days per year and invites you to explore the seven miles of easy, relatively flat hiking trails. An added bonus for children: The Refuge operates a nature center where you can view a variety of exhibits, turtles and snakes, and enjoy a touch table and special children's room. 

Long Pond Greenbelt Preserve
Bridgehampton/Sag Harbor Turnpike, Bridgehamtpon
The Long Pond Greenbelt Preserve is a series of wetlands that stretches from Ligonee Creek in Sag Harbor to Sagg Pond in Sagaponack. The combination of wetlands and forest make it a great spot for a hike and some leaf-peeping.

Long Island Grace Estate
Old Northwest Road, East Hampton
Once the home of three Native American villages, Grace Estate is now a beautiful spot for hiking. The main trail leads through woodlands of oak pine and borders a fresh water pond.

Peconic River - North Fork
If you're driving anywhere on the North Fork, you can't help but enjoy the vibrant colors all around you as you gaze out your car window.  A particularly scenic route is the Peconic Bay Boulevard, which runs along the Peconic River from Riverhead to Mattituck. This 12 1/2 mile route tends to have less traffic and is lined with parks and other places to stop and stretch your legs. 

Photo Courtesy of ILoveNY.com