East Lyme — The 37-acre Bayreuther property in the Oswegatchie Hills along the Niantic River is now officially preserved.

The closing on the undeveloped land abutting the 420-acre Oswegatchie Hills Nature Preserve took place Thursday morning.

“The hills are so important to all of us,” said Kris Lambert, president of the Friends of the Oswegatchie Hills Nature Preserve, a nonprofit organization, in a phone interview Thursday. “The Friends are very interested in protecting and preserving any of the land we can for the nature preserve.”

The parcel by Quarry Dock Road brings additional acreage to the nature preserve for both wildlife and trails, she said.

The organization and the state are holding conservation easements on the property now owned by the town.

The town paid $25,000 for the property, the state contributed $100,000 and a private foundation, The Thompson Family Foundation, donated $150,000. The Friends group is paying the remaining cost of the roughly $280,000 purchase price, plus any other costs associated with the closing.

“We’re just excited,” Lambert said. “I hope everyone in the town of East Lyme realizes what a precious piece of property the hills are. The Friends are doing everything we can to, first of all, protect what we have, and to acquire additional land. We’re always working towards that goal.”

Landmark Development, a Middletown-based company, has proposed over several years to build a residential complex on land it owns north of the preserve.