There are 99 US Post Offices in Allegheny County serving a total of 1,188,843 residents equating to 12,009 residents per post office. It's estimated that approximately 1,897,526 packages are handled across the 99 county post offices annually. Allegheny County (/\u00e6l\u1d7b\u02c8\u0261e\u026ani/) is a county in the southwestern part of the U.S. state of Pennsylvania. As of 2014 the population was 1,231,225, making it the second-most populous county in Pennsylvania, following Philadelphia County. The county seat is Pittsburgh. Allegheny County is included in the Pittsburgh Metropolitan Statistical Area. The county is in the Pittsburgh Designated Market Area. Allegheny County was the first in Pennsylvania to be given a Native American name, being named after the Allegheny River. The word \"Allegheny\" is of Lenape origin, with uncertain meaning. It is usually said to mean \"fine river\", but sometimes said to refer to an ancient mythical tribe called \"Allegewi\" that lived along the river long ago before being destroyed by the Lenape.