Was erected in March 1819, and contained all of Greenville Township that lay in Range 1 East, that is, all of Township 12 North, Range 1 East, and of Township 11 North, except the south tier of sections, which belonged to Twin Township. September 7, 1820, Washington Township was made to include all of townships 11, 112, 13, 14 and 15, Range 1 East. In December 1820, German Township was taken from the south end of Washington. It included the greater part of Township 11 North, but was bounded on the north by a line 40 rods north of the White River road. In December 1833, the north tier of sections of Township 11 North was taken in Washington Township, but was put into German Township a year later. Also, in December 1833, townships 13, 14 and 15 were taken from Washington and formed into Jackson Township.

The first settler in the township was Martin Cox, who settled in 1816 on land now owned by Samuel Cole, Jr. His brother Jacob Cox came to the township about the same time. John Snell and Christian Miller in 1817; Daniel Shively, Philip Rarick, Charles Sumption, Jr., Samuel Cole, Sr., Skidmore, Brady, and Elston in 1819; Jacob and John Chenoweth, 1820; and Edward Baldwin, Henry Creviston, Isaac Cherry, Thomas Thompson, David Wasson, Jesse Gray, 1819, and Thomas Beasley, were among the earlier settlers. Gray and Beasley were somewhat noted as "Indian hunters," that is, hunting Indians as others hunted wolves.

The first schoolhouse was built about 1822, on land now owned by Samuel Elston. There are now 11 schoolhouses, and 511 schoolchildren: 267 white and 17 colored males, and 217 white and 10 colored females.

The first church in the township, which was also the first in the county, was built by the Methodists in 1819, on land adjoining the farm now owned by John Hinning, in Section 36. It was also used as a schoolhouse and is still standing. There are now 3 churches in the township: a Campbellite, a United Brethren, and a Protestant Methodist.

Samuel Cole was the first Justice of the Peace.

There are now 64 miles of road, 27 of which are pike. In 1830 the population was 420; by the census of 1870 it was as follows:

Hillgrove was laid out in 1848.