From History of Madison County, Ohio, Chester E. Bryan, Supervising Editor, B.F. Bowen & Co., Indianapolis (1915)
Monroe township is one of the smallest in the county, and, in shape, is nearly that of an obtuse triangle. It lies in the north central part of the county and is one of the three townships that does not extend to the edge of the county. It is bounded on the north by Pike township and a fraction of a mile of Darby; on the east by Canaan and Jefferson townships; on the south and west by Deer Creek and Somerford townships. The following record is taken from the commissioners' report of March 16, 1819: "At a meeting of the commissioners, present, Burton Blizzard, Ira Finch and Patrick McLene, on petition being presented, ordered that the following bounds comprise a new township, to be known and designated by the name of Monroe: Beginning on the present line between Deer Creek and Pike townships, at the upper corner of Wallace's survey, running eastwardly, so as to cross Little Darby at the mouth of Barron run, to the original line between Pike and Darby townships; thence with the original line until it intersects Jefferson township line at Mark's survey; then to Henry Camp's lower corner; thence northwesterly with the new road leading to Urbana, including the same as far as to where said road crosses the London road; thence in a straight line to the place of beginning." In constituting Phelps township (now Canaan), in June of the same year, and subsequently, in enlarging Pike township by taking a portion off of Monroe township, its boundary lines were changed from the above description to its present lines and limits.
The principal streams and the only sources of drainage in the township are the Little Darby and Spring fork. The former courses through the entire township, in the central eastern portion, passing in a southeastern direction into Jefferson township; Spring fork enters Monroe township from its northwest corner, and meanders in a southeasterly course, nearly through the township, and empties into the Little Darby about one mile north of the south line of the township. The surface of this township is very level, except along these two creeks, where the land is somewhat broken and hilly. Especially along the Little Darby, on both sides for a little distance from the creek, the surface is quite broken, and in some places rather hilly. East of the stream, and between the Little Darby and Spring fork, the surface is very level after passing westward over a little undulating portion along Spring fork, then all westwardly is very level. In the western and central portions of the township, also in the southeastern part, are large farms. consisting of prairies and oak openings, which are most beautiful lands and peculiarly adapted to grazing purposes. The soil of these portions is generally a black loam, from one to three feet thick. It has in late years been ditched, tiled and drained, and since this work has been completed it produces all kinds of grain in abundance, and will vie in richness and productiveness with any lands in the county. Along the creeks, where the surface is undulating, the soil is generally a clay, but very strong and productive, and it can truly be said that Monroe ranks among the best townships of the county for stock and grain raising. The principal products are wheat, corn, potatoes and bay. The timber is similar to that of other townships in this part of the county. On the oak openings, burr oak, hickory and elm are the principal varieties. the former predominating. On the streams are some walnut, and the uneven and hilly portions, where the clay soil predominates, white, black and red oak, hickory. ash and some beech abound. But in this township the timber did not play an important part in the natural resources of the settlers and has been of minor importance, except to get it off the land in order to produce good pasturage and tillage.