The northernmost branches of the river are the West Fork, the East Fork (a.k.a. Skokie River) and the Middle Fork, which join into the North Branch at Morton Grove[?], Illinois. The North Branch meets up with the Main Branch of the Chicago River at Kinzie Street. The Main Branch flows due West from Lake Michigan, past the Wrigley Building and the Merchandise Mart[?].
The Chicago River has 45 movable bridges spanning it, down from a one-time high of 52 bridges. These bridges include several different types, including trunnion bscade, scherzer rolling lift, swing bridges and vertical lift bridges.
In the late 1700s, Jean Baptiste Point du Sable built his farm on the northern bank of the river and early in the next century, Fort Dearborn was built on the southern bank of the river. In 1915, the Eastland, an excursion boat docked at the Clark Street bridge, rolled over, killing 812 passengers. In 1828, the South Branch of the Chicago River was moved 1/4 miles west to make room for a railroad terminal. In 1992 the Chicago Flood occurred when a pilon punctured a hole in the bottom of the river into long unused tunnels beneath the river causing much of the Loop to flood.
Every year on St. Patrick's Day, the river is dyed green.