Lost River - Karst Information Portal

Manhole Cave, Corydon West 7.5-minute
quadrangle, Harrison County, Indiana,
was first discovered by bulldozing operations
during the construction of new State Highway
135 south of Corydon. The highway construc,
tion made use of the cave by building drainage
ditches and culverts which crain directly into
the cave. The entrance to the cave is a steel
manhole cover 2.5 inches thick weighing well
over 200 pounds. Underneath the steel cover is
a concrete pipe 37 feet deep. Steel rungs have
been placed on the side of the concrete pipe
to be able to descend to the bottom. At the
bottom is a horizontal concrete pipe 2 feet in
Flowstone on the laddder rungs.
Photo by Aaron Atz.
diameter which leads
to the actual cave.
The cave consists
of a short section of
passage forming a
small loop. The cave
contains a lot of mud
and debris washed
in through the
entrance. Breakdown
covers the floor in
some places. A few
speleothems exist
near the entrance,
and some larger
flowstone deposits
lie farther within.
No leads exist due to
extensive mud fill.
Manhole Cave
Harrison County Caves
Nick Smith in the climb-down entrance to Manhole Cave.
Photo by Aaron Atz.
By Greg Spaulding
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