Lowest and Highest Points in Tazewell County
Low elevation: <440 feet above mean sea level
Place: Illinois River
7.5' quadrangle name: Duck Island
PLSS: 3-17-23N-7W
Geology: Cahokia Alluvium in river valley
High elevation: >830 feet above mean sea level
Place: Unnamed hilltop
7.5' quadrangle name: Washington
PLSS: 3-11-26N-3W
Geology: Washington Moraine
Area: 650.28 square miles
Total relief (approximate): 390 feet
Average percent slope: 1.22%
Updated 10/1/2009 JKH