SAN BERNARDINO, Calif. — Stater Bros. Markets celebrated its 80th anniversary on August 17 by offering customers free balloons and cookies at all 168 of its supermarkets in Southern ­California.

“Celebrating 80 years is an unbelievable accomplishment for any company,” said Jack Brown, executive chairman for Stater Bros. “We wouldn’t be here without our valued customers, and this milestone is certainly a testament to the loyalty and dedication of all the past and present members of our Stater Bros. family, our devoted customers — many of whom are sixth generation Stater Bros. shoppers — and the partnerships which have been established with our supplier friends. We were founded by [World War II] veterans [Missouri-born twins Cleo and Leo Stater], and over 1,995 of us have served or continue to serve.”

Stater Bros. is the largest privately owned supermarket chain in Southern California and the largest private employer in San Bernardino and Riverside ­counties. And the company continues to expand: A grand opening was scheduled for August 24 for the first Stater Bros. supermarket in Ventura County, a 48,000-square-foot store in Simi Valley, about 30 miles from downtown Los ­Angeles.

“Stater Bros. is rooted in the American tradition, and we are a great fit in Simi Valley’s patriotic community,” said president and chief executive officer Pete Van Helden.

“We are excited to establish roots in a new community and look forward to acquainting Simi Valley customers with Stater Bros.’ extensive offerings and services,” Van Helden remarked.