PLEASANTON -- The East Bay Regional Park District has struck a deal to buy 1,367 acres in the foothills here for $6.2 million to expand Pleasanton Ridge Regional Park, officials announced Thursday.

Purchase of the Robertson Ranch land east of Palomares Road will protect large stretches of Sunol Ridge and provide areas to extend trails with panoramic views of the East Bay. The property includes the 2,163-foot-tall Sunol Peak.

Under a purchase option approved Tuesday by the regional park board, the agency expects to complete the purchase in December. The money will come from a 2008 regional park bond measure, grants and a surcharge on trash disposed at the Altamont Landfill near Livermore, park officials said.

The purchase will expand a large swath of protected lands in Pleasanton Ridge, Garin/Dry Creek and Vargas Plateau parks.

Pleasanton Ridge Regional Park is currently 7,500 acres. With the purchase it cover nearly 14 square miles.

Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff