If you are a fan of Wave Hill in the Bronx, you will want to visit this mansion on the other side of the borough. Similar to Wave Hill, you will find yourself at an estate surrounded by beautiful greenery and a coastline nearby. The grounds are not as extensive at Bartow-Pell, but there is plenty of space for a nice picnic and you can enjoy the grounds for free.
I highly recommend the guided tour of the mansion that takes place every 15 minutes past the hour from 12:15 to 3:15. You really get a feel for how the upper crust lived in the 1800′s. This mansion was built in 1790, and back in the day, its neighbors were other mansions. All the other mansions were destroyed in the late 1800′s to make way for Pelham Bay Park, but the city kept this one and rented it out for several decades before turning it into a museum.
Ideally, you will want to drive here, because the alternative is a subway ride and then a bus. Directions for car and public transportation can be found here. The mansion is open on Wed, Sat, and Sun from 12pm to 4pm. Some special events take place on these and other days. There are trails nearby that will take you to the bay, but beware of poison ivy and bring insect repellent.