When Disneyland opened in Anaheim, California, in July 1955, the park featured distinct areas dedicated to different kinds of kid-friendly fiction: Westerns, jungle adventures, fairy tales, and futuristic fantasy. Then there was another section, reflective of Walt Disney himself.
"Main Street, U.S.A." was meant to represent not just early 20th-century America but also the Missouri small town where Disney grew up. The company's design team polished and preserved an idealized version of its boss's youth, imagining a friendly, genteel community at the intersection of rural gumption and modern industry.
Source: http://www.avclub.com/