Inwood Hill Park at northern tip of Manhattan has hiking trails, old growth forest, and caves where Native Americans lived. Still technically Manhattan but feels like you're in the Catskills.

Take A train to 207th St, walk west to park entrance. Trails aren't marked well so bring phone for GPS. About 3 miles of trails total, perfect for half day escape from concrete.

Salt marsh area has surprising wildlife — Herons, hawks, occasional deer. Most tourists never make it this far north so you'll have it mostly to yourself.