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The Milltown site was located in Crawford County downstream from a dam and old mill site from which the town derived its name. Milltown is located off of State Road 64 and is split by the Blue River into A Crawford County Side and a Harrison County side. This site was visited on September 21 at 1:10 PM EDT. The weather at collection time was overcast and slightly cool with an air temperature of 65 degrees.
The general area directly around this site was unglaciated second growth forest. Beyond this was mainly residential area. The riparian area was steep wooded slopes mainly consisting of sycamore and silver maple trees.
Upstream from the riffle is the old mill dam. To the right is a very steep, partially wooded bank. Some evidence of erosion was noted here. To the right is a low slightly sloping bank. This bank was the location of the Cave Country Canoe operation. This side was cleared to a vast extent for the canoe businesses buildings. The only vegetation on this side was grasses and a few box elder trees.
Downstream, to the left the steep bank was farther from the river's main channel because of a large gravel outwash community and a race. This race had growths of water willow and several small silver maples. To the right the bank is higher and steeper than it is upstream. It is also slightly more wooded than upstream. On top of this bank was the canoe businesses gravel parking lot. Down from the parking lot, however, the bank and area beyond the bank turns into a forested area.
The physiographic region of this site was a mixed mesophytic forest that is part of the Eastern Deciduous Forest Biome, Shawnee Hills Natural Region, Escarpment Section. The soils of the area were Haymond Silt Loam.
The riffle itself was roughly 10 feet wide and 20 feet long. The average depth in the riffle was 9 inches with a maximum depth of 14 inches. Velocity of the riffle was 7 feet per second with a discharge of 71 cubic feet per second. Upstream from the riffle, as mentioned before was the old mill dam. Behind it was a large pool of roughly 9 feet. On the downstream side of the dam, a plunge pool of unknown depth had formed. This led directly into a glide zone and then into the riffle. Downstream from the riffle, the river turned into a swift, shallow glide. This area was roughly knee deep at most.
The substrate of the riffle was mainly bedrock. This bedrock was limestone of Mississippian age. Rocks and cobbles were scattered about on the bedrock with little sand or silt noted. Above the riffle there were some larger rocks and boulders. Below the riffle there were fewer rocks and boulders with mainly the bedrock as the river bed.
The dam was the only disturbance noted at this site.