The easement is located on 403 acres owned by the Hasterts in Crawford County, five miles north of historic Prairie du Chien in the Upper Mississippi River Valley, the Milwaukee Journal Sentinel reported Wednesday.
Hastert donated the easement through the Mississippi Valley Conservancy.
The transaction keeps the land in the former Illinois congressman's hands but bars the Hastert family from developing it.
Hastert received a tax break for putting the land in the conservancy but the conservancy said it did not know the value of his donation.
Hastert, a Republican, was speaker of the House from 1999 to 2007.
He represented Illinois in Congress for 20 years.