The area around Atherton Island Natural Area has an interesting geologic history. Atherton Island is an upland immediately east of Clinton, Indiana. It’s only about 300 feet above the surrounding area, but the edges rise quite noticeably from the floodplains on either side, of the Wabash River to the west and the much smaller Big Raccoon Creek to the east. As the name suggests, it was once a literal island in the Wabash River, but of course, is no longer. The “island” is about fifteen miles long, north to south, and is about five miles wide. The feature is quite visible using Google Maps’ satellite view, as it is outlined by the roads on both sides that hug the flat terrain directly adjacent to the upland (Zeller, 2021)

Atherton Island is located primarily in southwestern Parke County but includes 3-4 square miles of northern Vigo County. The town of Atherton is located about half a mile east of Route 41 on the Vigo/Parke County line and is at the western edge of the Island. Atherton Island begins about 2 miles south of Atherton. The town of Atherton and Atherton Island itself are named for a geologist (Baker, 1995).

Atherton Island was formed about 10 thousand years ago, when the glaciers were melting to the north, forming a much larger Wabash River than now. The glacial Wabash flowed south on both sides of Atherton Island, the main part of the river to the west and a much smaller part to the east where the northern part of Raccoon Creek now flows. Raccoon Creek originally flowed southwest from the Bridgeton area south of Rosedale and entered the Wabash River south of Atherton Island. However, the area northeast of North Terre Haute became blocked. Raccoon Creek could no longer enter the Wabash to the south and was forced to divert its course to the north for about ten miles, effectively reversing the southward flow of water on the eastern side of Atherton Island and entering the Wabash River north of the Island. Several ideas exist about how this blockage and reversal came about (Bartle, 1924; Dryer, 1913; Fidlar, 1948). However, no single hypothesis is adequate to explain the reversal (Wayne, 1966). Likely, the blocking of the valley northeast of Terre Haute was initially by ice. Outwash gravels and till were deposited in this area later, thus permanently blocking the area. Finally, sand settled upon this area, deposited by water first and then by wind, resulting in the formation of dunes. These dunes are visible today, especially north of the town of Sandcut in Vigo County.

As the glaciers thawed, the Wabash River eventually lowered to its present level, and Atherton Island was no longer surrounded by water. It is now a raised hilly area with Raccoon Creek to the east and flowing north and the Wabash River some two miles to the west flowing south.

It is possible to drive around the boundary of most of the Island via the following route: Take Rt. 41 northbound from Terre Haute towards Lyford. Lyford is on the immediate west side of the Island. Continuing north, Rt. 41 follows along the immediate west side of Atherton Island until it turns sharply eastward and goes up and across the Island for about a mile and a half, where it enters the Big Raccoon River valley and turns northward, crossing Big Raccoon Creek. If, instead of turning to the east on Rt. 41, you continue north on 600W; you will remain traveling along the immediate western edge of Atherton Island. About 4 miles north of the Rt. 41/600W junction and a fourth mile south of Raccoon Creek, turn right (east) on Coxville Road (originally Armiesburg Road), and you will skirt the northern edge of Atherton Island. In about half a mile, it turns south, and in a fourth mile, you will come to the NE corner of Atherton Island. Coxville Road then proceeds south along the immediate east edge of Atherton Island through Mecca and to Coxville. Rosedale is south of the most southeastern projection of Atherton Island. (Whitaker, 2018)

References

Baer, L. (2021). Map illustrations, Indiana geological and water survey scientist tour Atherton Island Natural Area. Ouabache Land Conservancy Newsletter, 2021, 8-9.

Baker, R. L. (1995). From Needmore to Prosperity: Hoosier place names in folklore and history. Indiana University Press.

Bartle, G. G. (1924). A change of drainage of Raccoon Creek, Parke County, Indiana. Indiana Academy of Science Proceedings, 34, 63-68.

Dryer, C. R. (1913). Wabash studies. Proceedings of the Indiana Academy of Science

Fidlar, M. M. (1948). Physiography of the lower Wabash Valley. Indiana Division of Geology Bulletin, 2, 112.

Wayne, W. J. (1966). The reversal of Raccoon Creek at Atherton Island, west central Indiana. Proceedings of the Indiana Academy of Science, 75, 167-174.

Whitaker, J. O. (2018). Atherton Island, Parke County, Indiana. Ouabache Land Conservancy Newsletter, 2018, 5.

Zeller, T. (2021). Indiana geological and water survey scientists tour Atherton Island Natural Area. Ouabache Land Conservancy Newsletter, 2021, 7.