In-N-Out is soon opening four more California locations, after expanding in December to Idaho with its 400th store, and more plans are underway in New Mexico and Tennessee.

In California, new stores are expected in Orange, Oxnard, Redlands, and Sylmar. Outside of California, a new store in Flagstaff, Arizona is also in the works, according to the company’s website.

Since the company’s first location in Baldwin Park, east of Los Angeles, it has expanded with locations throughout California, Arizona, Nevada, Utah, Texas, Colorado, and Oregon.

Also, earlier this month, the company opened its first store in Madera, California about 25 minutes northeast of Fresno.

To celebrate the chain’s 75th anniversary this year, current President and CEO Lynsi Snyder, the granddaughter of founders Harry and Esther Snyder, recently released a book “The Ins-N-Outs of In-N-Out Burger” which shares her firsthand experience of the multigenerational family-owned business, with behind-the-scenes photos, stories, and tales of her family’s Christian faith, which she said has helped shape her leadership with the company.

After the restaurant was founded by the Snyders in 1943, Ms. Lynsi Snyder became president in 2010, and the burger chain has continued to thrive under her guidance as she has stuck close to her family’s original family business motto, she told American Essence in a recent article.

The fundamentals of the business originate from what’s known as “Harry’s Bible,” a collection of managerial principles that address how to properly serve customers and treat employees.

“Most of the basics that my grandfather taught his managers are followed to this day,” Ms. Snyder told the magazine.

The chain is reportedly worth $3 billion.