There are 8 US Post Offices in Mecosta County serving a total of 39,775 residents equating to 4,972 residents per post office. It's estimated that approximately 63,485 packages are handled across the 8 county post offices annually. Mecosta County is a county located in the U.S. state of Michigan. As of the 2010 census, the population was 42,798. The county seat is Big Rapids. The county is named after Chief Mecosta, the leader of the Potawatomi Native American tribe who once traveled the local waterways in search of fish and game. Chief Mecosta was one of the signers the Treaty of Washington in 1836. The easily navigated waterways soon led to a boom in lumber industry growth. Workers settled the area in 1851, and the county was officially settled and the government officially organized in 1859. Mecosta County is home to over 100 lakes, rivers, and streams with the Muskegon River winding its way through the county seat and largest city Big Rapids (originally named Leonard). Mecosta County was set off on April 1, 1840, but remained attached for administrative purposes to Kent County until 1857, when it was attached to Newaygo County. The county government was organized on February 11, 1859. Mecosta County comprises the Big Rapids, MI, Micropolitan Statistical Area and is included in the Grand Rapids-Wyoming-Muskegon, MI, Combined Statistical Area."