REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Sunday, October 18th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m. and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend! Groups are welcome.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Sunday, October 18th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m. and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend! Groups are welcome.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Saturday, October 17th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m. and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend! Groups are welcome.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Saturday, October 17th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m. and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend! Groups are welcome.

Join the Friends of Princeton Open Space (FOPOS) and expert birder Winnie Hughes Spar for a guided bird walk through the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ. Together, we will observe Princeton's birds and learn about their fascinating habits!

BYO: Bring binoculars and water. Wear comfortable hiking shoes or sneakers; the trails can get muddy, especially around the lake.

Register for the Fall Bird Walk

Join us at Mountain Lakes House to discuss "A Sand County Almanac" by Aldo Leopold. Executive director of the Aldo Leopold Foundation, Buddy Huffaker will be joining the discussion.

Presented in partnership with the Princeton Public Library and the Princeton Environmental Film Festival, this series is dedicated to readings about conservation, stewardship, and our relationship with nature. Led by Diana Newby, FOPOS board member and Associate Director of Writing at Princeton University, each meeting includes a discussion of the book and an accompanying activity. Registration is requested.

Sign up for this session via Princeton Public Library. You do not need to be a library cardholder to register.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Wednesday, October 14th. There will be a morning volunteer session from 10 a.m. to 12 p.m. Bring a friend! Groups are welcome.

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Saturday, October 10th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m. and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend! Groups are welcome.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with the Friends of Princeton Open Space (FOPOS) on Saturday, October 10th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m. and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend! Groups are welcome.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, October 3rd. There will be two sessions: the morning session will be from 9 to 11 am and the afternoon session is from 12 to 2 pm. Bring a friend, and groups are welcome!

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, October 3rd. There will be two sessions: the morning session will be from 9 to 11 am and the afternoon session is from 12 to 2 pm. Bring a friend, and groups are welcome!

Join Friends of Princeton Open Space on Sunday, September 19th for our annual Fall Fest fundraiser at the Mountain Lakes House, overlooking the beautiful lake at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, New Jersey.

🎶 Live Music

🌱 Delicious Fall Foods with Plant-Based Options

🍻 Craft Beverages

🌻 Nature-Themed Fun

• Tickets:

  • Early Bird: $60 per person — ends 9/12

  • General Admission: $70 per person — starting September 13

  • Children 12 and under: Free, but registration is required

  • Ticket payments made by check can be made payable to "Friends of Princeton Open Space" and mailed to PO Box 374, Princeton, NJ 08542.

Become a Fall Fest Sponsor

• White Oak Champion – $2,500 (Includes 10 tickets)

• Red Maple Guardian – $1,000 (Includes 6 tickets)

• Pawpaw Tree Protector – $500 (Includes 4 tickets)

• Serviceberry Supporter – $250 (Includes 2 tickets)

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, September 12th. There will be two sessions: the morning session will be from 9 to 11 am and the afternoon session is from 12 to 2 pm. Bring a friend, and groups are welcome!

Join the Friends of Princeton Open Space (FOPOS) and expert birder Winnie Hughes Spar for a guided bird walk through the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ. Together, we will observe Princeton's birds and learn about their fascinating habits!

BYO: Bring binoculars and water. Wear comfortable hiking shoes or sneakers; the trails can get muddy, especially around the lake.

Register for the Fall Bird Walk

Join us for our August Nature Walk through the trails of the Billy Johnson Mountain Lakes Nature Preserve.

Led by the Friends of Princeton Open Space summer interns, we'll observe the great diversity of life at the Preserve with possible sightings of eastern painted turtles, great blue herons, beavers, salamanders, crayfish, and macroinvertebrates. Learn about various plant species and habitat restoration projects aimed at preserving native organisms. After our walk, we’ll head back to the Mountain Lakes House to delve into the world of macroinvertebrates collected during our walk. Using field microscopes, we'll explore the diversity of plants & waterbugs and discover their role as indicators of ecosystem health.

Sign up for our August 21 Nature Walk on Eventbrite

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Wednesday, August 19th. There will be a volunteer session from 3 pm to 5 pm. Bring a friend, and groups are welcome!

Join us for our August Nature Walk through the trails of the Billy Johnson Mountain Lakes Nature Preserve.

Led by the Friends of Princeton Open Space summer interns, we'll observe the great diversity of life at the Preserve with possible sightings of eastern painted turtles, great blue herons, beavers, salamanders, crayfish, and macroinvertebrates. Learn about various plant species and habitat restoration projects aimed at preserving native organisms. After our walk, we’ll head back to the Mountain Lakes House to delve into the world of macroinvertebrates collected during our walk. Using field microscopes, we'll explore the diversity of plants & waterbugs and discover their role as indicators of ecosystem health.

Sign up for our August Nature Walk on Eventbrite

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, August 15th. There will be a morning session from 9 am to 11 am. Bring a friend, and groups are welcome!

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, August 8th. There will be two sessions: the morning session will be from 9 to 11 am and the afternoon session is from 12 to 2 pm. Bring a friend, and groups are welcome!

Join us at Mountain Lakes House to discuss "Wild Dark Shore" by Charlotte McConaghy. Following the discussion, we will have a demonstration on native seed collection and propagation.

This series is presented in partnership with the Princeton Public Library and the Princeton Environmental Film Festival, and is dedicated to readings about conservation, stewardship, and our relationship with nature.

Sign up for this session via Princeton Public Library. You do not need to be a library cardholder to register.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Wednesday, August 5th. There will be a morning session from 9 am to 11 am. Bring a friend, and groups are welcome!

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, July 25th. There will be two volunteer sessions; the morning session is from 9 a.m. to 11 a.m., and the afternoon session is from 12 p.m. to 2 p.m. Come to one or both. Bring a friend and groups are welcome!

Sign up for Moth Night via Eventbrite.

Celebrate Moth Week with Friends of Princeton Open Space!

Join FOPOS's stewardship team for an evening moth survey at the Billy Johnson Mountain Lakes Nature Preserve. Moths are fascinating creatures and contribute vital ecosystem services as pollinators and as prey, especially so for baby birds, which primarily rely on caterpillars and other insects for food.

During this session, participants will observe, identify, and learn more about these mysterious night creatures. The program will begin with an educational presentation about moths, led by Patrick Natale, Assistant Professor of Biology at Mercer County Community College, followed by a hands-on activity where participants will log biodiversity data at the Preserve.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Wednesday, July 8th. There will be an afternoon session from 3 pm to 5 pm. Bring a friend, and groups are welcome!

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Sunday, July 19th. There will be an afternoon session from 12 p.m. to 2 p.m. Bring a friend, and groups are welcome!

Sign up for this session via Eventbrite.

Wineberries are one of New Jersey's most abundant summer brambleberries, but they are also very invasive and outcompete native plants. Fortunately, they are delicious and YOU can help us curb their spread by eating them!

Join local experts Matt and Shannon for a wineberry forage walk at the Billy Johnson Mountain Lakes Nature Preserve in Princeton. During this volunteer stewardship session, participants will learn about the origins of wineberry and how to identify this invasive plant--and then we will get picking! Folks will get the chance to take their wineberry harvest home. A recipe card will be included so that you can make wineberry jam at home!

Join us for our July Nature Walk through the trails of the Billy Johnson Mountain Lakes Nature Preserve.

Led by the Friends of Princeton Open Space summer interns, this guided walk will offer a chance to explore lush trails and vibrant summer blooms. Whether you’re a seasoned hiker or a first-time visitor, it's the perfect way to enjoy the outdoors and reconnect with nature. Our stewardship team will also share insights into the history of the preserve and the ongoing land stewardship efforts that help protect this special place for future generations.

Be sure to wear sturdy, weather-appropriate footwear. Feel free to bring a camera or binoculars along to help you spot and capture the beauty of wildlife as we explore.

Sign up for our July Nature Walk on Eventbrite