There are 12 US Post Offices in Ellis County serving a total of 148,773 residents equating to 12,398 residents per post office. It's estimated that approximately 237,458 packages are handled across the 12 county post offices annually. Ellis County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 149,610. The county seat is Waxahachie. The county was founded in 1849 and organized the next year. It is named for Richard Ellis, president of the convention that produced the Texas Declaration of Independence. Ellis County is included in the Dallas-Fort Worth-Arlington, TX Metropolitan Statistical Area."