In 1920, former Philadelphians John and Marian Horwitz O'Brien and Tampa banker A.C. Clewis came to Clewiston when it was just a tiny farming and fishing community called Sand Point. They, along with Bernard G. Dahlberg, a Chicago businessman, discovered that soil surrounding Lake Okeechobee was ideal for growing sugar cane and created the Southern Sugar Corp.

In 1931, the company reorganized as U.S. Sugar Corp., which is still the biggest landowner and largest employer in Clewiston. The company has recently negotiated with the State of Florida to sell the entire company and land to the South Florida Water Management District and lease it back to operate it's sugar mills.