[2] It has the highest population density of the Warren County townships at about 120 inhabitants per square mile (46/km2).

Big Pine Creek flows through the far northeastern corner of the township on its way to the Wabash River.

For much of its route through the township, it parallels State Road 28, running just south of the highway.

[16] Washington Township is part of the Metropolitan School District of Warren County.

[18] Washington Township has a trustee who administers rural fire protection and ambulance service, provides relief to the poor, manages cemetery care, and performs farm assessment, among other duties.