There are 14 US Post Offices in Seminole County serving a total of 426,535 residents equating to 30,467 residents per post office. It's estimated that approximately 680,797 packages are handled across the 14 county post offices annually. Seminole County (/\u02c8s\u025bm\u1d7bno\u028al/, SEM-i-nohl) is a county in the state of Florida. As of the 2010 census, the population was 422,718. Its county seat and largest city is Sanford. Seminole County is included in the Orlando-Kissimmee-Sanford, FL Metropolitan Statistical Area."