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Cawthra Mulock Nature Reserve

Explore the accessible trail spanning 538 metres to see red fox, great blue herons, red-tailed hawks, great-horned owls and much more.

Cawthra Mulock Nature Reserve © Mark Carabetta


Donated to Ontario Nature in 2003, the Cawthra Mulock Nature Reserve is a valuable contribution towards the conservation of nature. Julyan Mulock and the Cawthra Mulock Foundation generously donated the 107-hectare (265-acre) property, ensuring that the land would be protected in perpetuity.

During the 31 years that the Mulocks lived on the property, they made a number of contributions towards its naturalization. Over 10,000 pines were planted in the old fields. Many of the old fields were allowed to regenerate naturally and are now important habitat for a variety of sparrows and other meadow birds.

Orange jewelweed, Cawthra Mulock Nature Reserve © Maria Papoulias


In 2007, the York Simcoe Nature Club became the official stewards of the Cawthra Mulock Nature Reserve. The group is actively assisting with restoration, monitoring and access improvement projects on the property.

If you are interested in assisting or joining the club, please email yorksimcoenatureclub@gmail.com.

Periwinkle pull, Cawthra Mulock Nature Reserve © Smera Sukumar

Plants and Animals

Surrounded by intense agricultural and urban development, the nature reserve provides refuge to a variety of wildlife. The most notable feature of this property is the diversity of habitats it encompasses. The property hosts a large tract of mature hardwood and mixed forests. Enormous beech trees rub shoulders with tall maples and hemlock. A small wetland area, dominated by birch trees and larch, is part of the larger Ansnorveldt wetland complex.

Located in the West Holland River watershed, the property boasts two creeks. White-tailed deer, red fox, great blue herons, red-tailed hawks and great-horned owls are just a few of the residents that call this nature reserve home.

Red fox © Peter Ferguson


Located just north of Newmarket, the property is a valuable green space in a highly developed area of Ontario. The York Region Greening Strategy identifies it as a key natural area. The property also falls within the context of the Government of Ontario’s Greenbelt system. Situated just north of the Oak Ridges Moraine, the rolling hills and forested ridges are a refuge for wildlife.

Come visit Ontario Nature’s first accessible trail! This 538-metre trail includes guiding ropes, is graded to a maximum of 10% for 20 metres and the surface is pea gravel. There is also a system of well-marked trails, including interpretive signs.

View a trail map of Cawthra Mulock Nature Reserve here.

Southern Ontario, like our nature reserves, is experiencing an increase in black-legged ticks and with it an elevated risk of contracting Lyme disease. Please stay on trails are read more precautionary measures to avoid Lyme disease in our blog post.

Accessible trail bench, Cawthra Mulock Nature Reserve © Smera Sukumar

“We are committed to exploring ways to improve accessibility at our nature reserves with trails, ensuring that we balance ecological integrity with improving people’s access to nature.”

– Tanya Pulfer, former Conservation Science Manager

Accessible trail at Cawthra Mulock Nature Reserve © Noah Cole


The bridge was removed due to structural issues. Please access the western portion of the trail network to the upper portion of the forest-meadow trail. Please do not cross the stream by foot as it degrades this sensitive habitat. We are currently fundraising to replace the bridge and welcome donations towards this project.

Monarch butterfly on milkweed © Jenna Siu


The nature reserve can be accessed by travelling north on Bathurst Street from Green Lane/Millers Side Road. The nature reserve is the second driveway on the left (west) side at 18462 Bathurst Street and is marked by a green and white Ontario Nature sign.

The parking lot is located across from the white house (please respect the privacy of the tenants). The trails network can be accessed directly from the parking lot, past the gate.

We do not charge a fee for entrance and there are no operating hours on any of our nature reserves. Properties are monitored by volunteer stewards. We rely on visitors to be safe, minimize their impact on nature and be respectful of others. For more information about visiting the nature reserves, please read our Permitted Activities Policy.

We welcome donations to support this nature reserve and our system of 26 nature reserves.

Widow skimmer dragonfly at Cawthra Mulock Nature Reserve © Noah Cole

Bobolink © David Watkins
Cawthra Mulock Nature Reserve

The Cawthra Mulock Nature Reserve is generously supported by:

Special Notice

Cawthra Mulock Nature Reserve will be closed on June 26th, 2024 for the final periwinkle treatment along the main trail - and will reopen on June 27th.

As of April 1, 2023, dogs are not permitted at Cawthra Mulock Nature Reserve. Guide dogs or other service animals are allowed. You can learn more about these changes here.

If you have any questions, please call 1-800-440-2366 or email info@ontarionature.org.