So enduring is the cheeseburger's legacy that we now have a national day of celebration honoring the menu item—September 18—a day when diners across the country can land free and discounted burgers at a variety of outlets.

Of course, the other 364 days of the year are perfectly legit occasions to indulge in a cheeseburger too—you just need to know where to go. Your first stop? California.

The cheeseburger is serious business in the Golden State. Whether it's a double Waygu beef cheeseburger at an upscale restaurant in Los Angeles, a bacon cheeseburger on the beach in San Diego, or a blue cheese cheeseburger at a Wine Country bistro, you're never far from a next-level burger experience. The reverence for the country's culinary phenomenon is apparent across the state, from hole-in-the-wall diners to Michelin-starred restaurants.

And if you believe the prevailing theory on the origin of the sandwich, California's devotion to cheeseburgers should come as no surprise. As the story goes, a teenage fry cook named Lionel Sternberger made history at a Pasadena restaurant in 1926 when he dropped a piece of cheese on a burger he was grilling just to see what would happen. When his experiment proved an unmitigated success, word spread and fry cooks across the country were soon slinging cheeseburgers to eager diners everywhere.

Here’s a quick rundown of some of the must-try burgers in California.

Where It All Began, Pasadena
While the Rite Spot, where Lionel Sternberger made history, is no longer in existence, you can still get a great cheeseburger in Pasadena. Try Umami Burger's Cali, featuring butter lettuce, roasted tomato, caramelized onions, and house-made cheese, or Sandy's Green Chile Burger at La Grande Orange, featuring roasted green chiles and melted cheddar. You can also check out more burger joints in Pasadena that will be celebrating with specials. Pasadena, it should be noted, also boasts an entire week devoted to cheeseburgers in January.

Land of the Burger, Los Angeles
While the cheeseburger was born in Pasadena, it came of age in nearby Los Angeles. There are too many quality options to list, but Discover LA offers up a few that you can't miss when you're in town. Pay special attention to the options at Belcampo, The Bottle Room (which boasts blue cheese and fig jam burgers cooked in duck fat), and Fundamental LA.

The Original Patty Melt, multiple locations
The Los Angeles County mainstay Norms Restaurant claims that Norm himself invented this popular cheeseburger variant. Go for “Norm's Original Patty Melt”—a ground chuck patty on grilled rye bread with melted American cheese and caramelized onions.

In-N-Out Burger, multiple locations
Perhaps California's most famous burger joint, this fast food chain began with a single restaurant in Baldwin Park and has turned its cheeseburgers into a national obsession. So much so that it even has a “not-so-secret” menu. Visitors and locals flock to enjoy cheeseburgers in multiples of four (the “4x4”), Animal Style (with cheese and onions), Monkey Style (Animal Style, with fries jammed in), sans bread (that's right, it's just two burger patties sandwiching slices of cheese), and more. It's such an experience that there are multiple online guides to hacking the In-N-Out Burger menu.

Burgers by the Beach, San Diego
When you order a burger at Hodad's in Ocean Beach, you're getting a side of fun in the California sun. Famous for its double bacon cheeseburgers, you also have the option to go for the menu's $99 “all you can eat” offering. Beach burgers, incidentally, are a phenomenon throughout the Golden State, as this article proves.

Wine Country Burgers, Napa Valley
Mustards Grill, brought to life by San Francisco Chef Cindy Pawlcyn, offers a juicy, half-pound cheeseburger topped with Maytag blue cheese with a side of homemade pickles. When paired with a sturdy Napa Cabernet Sauvignon, it's a definitive Wine Country experience. And so is Gott's Roadside, where you can find a range of inventive cheeseburger offerings including a kimchi burger, a Wisconsin sourdough, and the “Impossible” cheeseburger that's made entirely from plants. Don't believe us? Watch this video.

Often imitated, never duplicated, San Francisco
Zuni Café burger patties are so beloved, Chef Judy Rodgers' recipe is all over the Internet, raved about far and wide, from Martha Stewart to Food & Wine magazine. Eater SF lauds the cheeseburger for being perfectly juicy, thanks to the special method of salting the meat the night before cooking and grinding it up just before. It comes with a rosemary focaccia bun, pickled onions, and garlic aioli. If you can’t get a reservation, Eater SF offers up a few more suggestions for essential burgers.