From History of Madison County, W. H. Beers & Co, Chicago, 1883
The surface is generally level; the western and southern portions being particularly flat and uniform, while the northern and eastern portions are undulating, and in some localities, along the creeks, is quite hilly. The principal streams are Deer Creek and Oak Run and Bradford's Fork, with their tributaries; the former passes through the northeast portion of the township, in a southeasterly course, entering the township from Union Township by passing through the farm of Joseph Bell and striking in its course the boundary line of Fairfield Township, there takes a south course and for some distance forms the boundary line between Oak Run and Fairfield, then again enters Oak Run Township through the Chenoweth farm and reaching the north line of Jesse Rea's farm, turns east, reaching the Dun tract of land again takes a south course and passes into Pleasant Township. In its course through this township, it receives its first tributary in what is called Nigger Run; then it receives on the Cephas Pancake farm, Glade Run, which enters the northeast corner of the township, passes through four or five farms, and empties into Deer Creek as above mentioned. Next it receives, on the Chenoweth farm, Oak Run, which enters the township through the Dock Williams farm and flows southeasterly, receiving in its course through the Chrisman land Walnut Run, which courses through the Jesse and Robert Rea farms and a part of said Chrisman land, and empties, as stated, into Oak Run. A little below where it empties into Deer Creek, the latter receives on the Jerry Rea land, Turkey Run. In the south part of the township and forming for a considerable distance the boundary line between Oak Run and Range Townships is Bradford's Fork, the main stream having a general southeastern direction, receiving on the D. B. Foster farm its North Fork, and farther down, on the Gwynne land, receives Barron Run. These numerous streams and their tributaries furnish an abundant supply of water to all portions of the township. The west and south portions of the township possess a very deep, rich soil, principally a black loam, and as originally found by the frst settlers, consisted mainly of oak openings and prairies, upon much of which grew a sedge so tall that a man riding through it on horseback could take the grass from either side and tie the tops together over his horses' back. The northern and eastern portions and along the creeks, where the surface is undulating and hilly, possesses principally a loam and clay soil, and, although some small portions of it is a thin soil, yet the most of it is strong and productive, and is excellent for either grass or grain.