In 1963, Dick Portillo started Portillo's hot dog stand in Villa Park, IL, which he called "The Dog House." Years later, Portillo's has become a brand synonymous with Chicago. People say it's not a real trip to Chicago unless you eat at Portillo's. There are more than 70 locations across several states of Portillos'. They are famous for the Chicago Hot Dog containing mustard, relish, celery salt, freshly chopped onions, sliced red ripe tomatoes, kosher pickles, and sports peppers piled onto a steamed poppy seed bun.