There are 1 US Post Offices in Wibaux County serving a total of 1,017 residents equating to 1,017 residents per post office. It's estimated that approximately 1,623 packages are handled across the 1 county post offices annually. Wibaux County (/\u02c8wi\u02d0bo\u028a/ WEE-boh) is a county located in the U.S. state of Montana. As of the 2010 census, the population was 1,017 making it the fourth-least populous county in Montana. Its county seat is Wibaux."