For those who regard Allegheny County as a built-out and paved-over urban expanse, we have two words: Sycamore Island.

This 14-acre wilderness -- yes, you read that right -- sits in the Allegheny River near Blawnox. It's the last undeveloped, privately owned island in the county, and thanks to the Allegheny Land Trust it's going to stay that way.

Last week, the trust purchased the island, a hardwood floodplain forest full of silver maples, from Mirric Realty Inc. for $250,000. The money came from a grant by the Colcom Foundation in Pittsburgh, which supports conservation, environmental sustainability and natural resource preservation.

The nonprofit, Sewickley-based land trust said the purchase "will create a unique opportunity for the public to visit and experience a wild and natural island within an urban county." It knows something about that, having bought and protected more than 1,350 acres of land in 18 municipalities since 1993.

Because of the efforts of groups like the Allegheny Land Trust -- and the contributors, both large and small, who give them buying power -- there is much more to Allegheny County than cities, roads, towns and bridges. There are preserved hillsides, protected streams and now ... Sycamore Island.