Land for sale in Arkansas's Sebastian County recently totaled $125 million and around 3,000 acres. Sebastian County ranks 24th in the Natural State for the total number of acres of land currently advertised for sale. Fort Smith had the most land for sale. From an economic perspective, manufacturing and related services are the main sectors in Sebastian County. Sebastian County is the 74th biggest county (547 square miles) in Arkansas. It's located in the River Valley Arkansas region of Arkansas.