Texas Township in Iowa, USA Jefferson Township is a township in Mahaska County, Iowa, United States.[1] References ^ U.S. Geological Survey Geographic Names Information System: Jefferson Township, Mahaska County, Iowa Municipalities and communities of Mahaska County, Iowa, United StatesCounty seat: OskaloosaCities Barnes City‡ Beacon Eddyville‡ Fremont Keomah Village Leighton New Sharon Oskaloosa Pella‡ Rose Hill University Park Map of Iowa highlighting Mahaska CountyTownships Adams Black Oak Cedar East Des Moines Garfield Harrison Jefferson Lincoln Madison Monroe Pleasant Grove Prairie Richland Scott Spring Creek Union West Des Moines White Oak Unincorporatedcommunities Cedar Hopewell Indianapolis Lakonta Peoria Tioga Union Mills Wright Footnotes‡This populated place also has portions in an adjacent county or counties Iowa portal United States portal 41°13′N 92°49′W / 41.217°N 92.817°W / 41.217; -92.817