Jackson Hole's back yard and the national park that houses the iconic Grand Teton is getting ready to get even grander this weekend. Grand Teton National Park will mark its single largest expansion since 1950, with the donation of nearly two square miles (1,106 acres) of land at the park's south end.

The growth is a gift from the Rockefeller family in conjunction with the National Park Service. The parcel, with an estimated worth of $160 million (or closer to $1 billion if you factor in current Jackson Hole real estate prices), is the last part of the JY Ranch, owned by the Rockefellers, to be donated to the park. It sits on the shore of Phelps Lake. The family donated the land in November and will commemorate the event with a private ceremony this Saturday. In the months leading up to the donation, the Rockefellers removed 30 buildings from the land, donated 13 others as employee housing and moved 17 to another one of their properties in the Jackson Hole area. Roads were removed and eight miles of trail were built.

Perhaps the most significant portion of the gift besides the land is the 7,500-square-foot visitor center built with green technology, also donated by the Rockefellers. The visitor center coupled with the land donation is estimated to be one of the most valuable gifts in park system history.

For additional information about visiting Grand Teton National Park, click here.