The county is part of the North Central Pennsylvania region of the state.

Warren County also contains a tract of old-growth forest called Hearts Content National Scenic Area.

22.2% were of German, 12.4% Swedish, 11.2% American, 10.5% Irish, 8.8% English, 8.2% Italian, and 5.1% Polish ancestry.

[20] Chart of Voter Registration per Education Names and Addresses directory which is annually developed by the Pennsylvania Department of Education, 2016 Under Pennsylvania law, there are four types of incorporated municipalities: cities, boroughs, townships, and, in at most two cases, towns.

The following cities, boroughs and townships are located in Warren County: Census-designated places are geographical areas designated by the U.S. Census Bureau for the purposes of compiling demographic data.

The population ranking of the following table is based on the 2010 census of Warren County.