Blue Mountain Reservation Welcher Ave, Peekskill, NY10566 Blue Mountain is one of Westchester County's largest parks. It is located in the center of the town of Cortlandt, with…More its northeastern corner in the city of Peekskill. Blue Mountain is known for its hiking and mountain biking trails. A small lake and beach are enjoyed by families and summer day-campers. There are picnic tables and grills near the lake. A county park pass is not required, but it does come with a parking discount. At the southern end is the Sportsmen's Center, providing archery, pistol and rifle ranges. Free instruction is available from range experts. Children under 12 are not allowed to use the facilities of the Sportsmen's Center. The fees for the center are listed on the county's website.