Harford County GovernmentHarford County Zip Code boundaries. 2017 Maryland State Data CenterArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/30da3a6d0a194876b03afc86845553fe_0engHarford County Planning and Zoning Open GISPublicZip Code Boundaries [Maryland--Harford County]Web servicesMaryland--Harford CountyMarylandLast Modified: 2021-10-29