SOUTH KINGSTOWN — The town is working to secure state and federal money to stave off development of a 33-lot subdivision on Route 1, across from the Village at South County Commons.

Six years ago developers won approval to build Castle Farm, a sprawling development on 123 acres just north of The Prout School. The town is now estimating the cost of the land at about $4.2 million and is cobbling together a deal to preserve it, Principal Planner Ray Nickerson said yesterday.

South Kingstown is seeking $2.1 million from the state Coastal Resources Management Council through a National Oceanic and Atmospheric Administration grant program and another $400,000 from the state Department of Environmental Management. An additional $1.1 million would come from the U.S. Fish and Wildlife Service, with the town contributing $606,000, he said.

Formerly farmlands, the property contains pastures, woods and wetlands that fall within the Narrow River special management area. It abuts the John H. Chafee Wildlife Refuge and other conservation lands held by the Audubon Society of Rhode Island and the Narrow River Land Trust.

In addition to providing habitat for wood thrush and Canada warbler, the land is a likely stop for migratory birds such as the dark-eyed junco, Cooper’s hawk and northern saw-whet owl.

Landowner Thomas P. Ricci expressed a willingness to sell development rights to 111 acres when approached by Fish and Wildlife officials, Nickerson said. Four building sites would remain, two of which already have houses, he said. Ricci, of the Tower Hill Group LP, could not be reached for comment yesterday.

An appraisal will be conducted in the coming weeks, Nickerson said.