Eagle Marsh is a large complex of restored wetlands on the western edge of Fort Wayne, Indiana. The main part of it is on the south side of Engle Road Extended, west of Smith Road. Other sections of it are located on the northeast and southeast corners of Engle Road and Smith Road.

Until the late 19th Century, much of southwestern Allen County, including a large area that is now within the city of Fort Wayne, was a large swamp that extended all the way to Huntington. The Little Wabash River, now known simply as the Little River, starts near the current site of the Hanson Limestone Quarry on Ardmore Avenue in Fort Wayne and flows southwest to Huntington, where it empties into the Wabash River. The Little River went through the middle of the swampland. In the late 1800s, the swamp was systematically drained and the flat land became farmland.

In 2005, an organization called The Little River Wetlands Project began restoring the marsh on the 676 acre plot of land between Engle Road and the railroad tracks, west of Smith Road. They later acquired the other areas east of Smith Road, growing the restored wetland to 831 acres.