Linn county is located in east central Iowa in the third tier of counties west of the Mississippi river. It is bordered by Benton county on the west, Johnson on the south, Jones on the east and Buchanan and Delaware on the north. It is partly in the Iowan drift soil area and partly in the Mississippi loess area. Its upland soils are therefore partly glacial in character and partly loessial, the larger area being covered by the drift soils.