Saint Clair County topographic maps

Average elevation: 427 ft

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Average elevation: 459 ft

Average elevation: 417 ft

Average elevation: 400 ft

Average elevation: 489 ft

Average elevation: 499 ft

Average elevation: 538 ft

Average elevation: 443 ft

Average elevation: 453 ft

To the south of Monks Mound is the Grand Plaza, a large area that covered roughly 50 acres (20 ha) and measured over 1,600 ft (490 m) in length by over 900 ft (270 m) in width. Researchers originally thought the flat, open terrain in this area reflected Cahokia's location on the Mississippi's alluvial flood…

Average elevation: 420 ft

Average elevation: 515 ft

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Average elevation: 568 ft

Average elevation: 499 ft

Average elevation: 420 ft

Average elevation: 531 ft

Average elevation: 558 ft

Average elevation: 456 ft

Average elevation: 518 ft

Average elevation: 489 ft