SACRAMENTO (CBS13) – One of America’s most beloved fast food restaurants is celebrating its birthday on Monday.

A favorite of high-end chefs and millions of Californians alike, In-N-Out Burger is turning 70.

The burger chain was founded in Baldwin Park back on Oct. 22, 1948. To mark the occasion, the restaurant will be releasing its 2019 t-shirt collection.

Southern Californian burger chain ‘In-n-Out Burger’ open a pop up restaurant in Swiss Cottage, London. (Credit: Ming Yeung / Contributor)

You want this, don’t you? (Credit: Ming Yeung / Contributor)

Known for its simple menu but high-quality ingredients, In-N-Out’s fan base includes chefs like Gordon Ramsay and Anthony Bourdain. Just this past year, the chain was voted – again – as America’s favorite quick-service restaurant by Market Force.

In-N-Out Burger was founded by Harry and Esther Snyder and is still family owned.

The chain is known for its policy of slow, deliberate growth that keeps the restaurants family-owned instead of franchised.

There are now more than 300 In-N-Out restaurants spread across six states.