Jack in the Box on Encinitas Boulevard traces directly to San Diego, where the chain was founded on February 21, 1951, as the first fast-food restaurant to pair a drive-through window with a two-way intercom system. The Encinitas location carries the full late-night and breakfast menu — including the Breakfast Jack sandwich format introduced in 1964 as the first breakfast item in the national fast-food industry — adding early- and late-hour dining options to the Encinitas Boulevard commercial corridor near Leucadia Pizza Encinitas. The taco remains the chain's highest-volume individual item, with systemwide sales exceeding 554 million units per year, served in a proprietary crispy corn shell that has remained on the menu since the original San Diego location. A menu spanning burgers, chicken, tacos, egg rolls, teriyaki bowls, and curly fries makes the format one of the most category-diverse in the national fast-food segment, covering breakfast, lunch, dinner, and late-night dayparts from a single kitchen line. That cross-category architecture — combining Mexican, Asian, and American items under one roof — positions the Encinitas Boulevard location as a late-night alternative to the single-cuisine specialists on the same corridor, including Chin's Szechwan Encinitas. The two-way intercom drive-through system conceived in 1951 remains the operational backbone of all 2,200-plus locations, processing orders through a dedicated speaker-and-screen assembly calibrated for vehicle-lane throughput.