High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Jefferson Township is one of twenty townships in Allen County, Indiana, USA. As of the 2000 census, its population was 1,958. According to the United States Census Bureau, Jefferson Township covers an area of 36.39 square miles (94.24 square kilometers); of this, 36.37 square miles (94.19 square kilometers, 99.95 percent) is land and 0.02 square miles (0.05 square kilometers, 0.05 percent) is water.