2024 Map of Seneca

About this map

The Illinois River corridor defines the landscape of this LaSalle and Grundy County border region, where modern infrastructure meets 19th-century transport routes. At the center of the sheet, Seneca sits at the intersection of river traffic and the historic I & M Canal, a legacy of the era's waterway expansion. The terrain is marked by significant hydrological features, from the large LaSalle County Nuclear Station Cooling Pond in the southwest corner to the network of smaller runs like Deadly Run and Hog Run that drain into the river valley. To the east, the settlement of Langham and prominent elevations like Holderman Hill overlook the floodplain. The map captures the continued importance of the river islands, including Barry Island and Grist Island, alongside local landmarks like Mount Calvary Cem, providing a detailed view of the area's contemporary development and preserved open spaces.