Lowest and Highest Points in La Salle County
Low elevation: <445 feet above mean sea level
Place: Illinois River
7.5' quadrangle name: Spring Valley
PLSS: 3-19-33N-1E
Geology: Cahokia Alluvium in river valley
High elevation: ~910 feet above mean sea level
Place: unnamed hilltop
7.5' quadrangle name: Sublette
PLSS: 3-5-36N-1E
Geology: La Moille / Paw Paw Moraines
Area: 1,137.41 square miles
Total relief (approximate): 465 feet
Average percent slope: 1.03%
Updated JKH 9/30/2009