Great Loop: Chicago River & Chicago Sanitary and Ship Canal Guide

The Chicago River and the Chicago Sanitary and Ship Canal play a crucial role within the Great Loop route, as they serve as the link between Lake Michigan and the Illinois Waterway. Loopers, moving southward from the Great Lakes, will have to go through downtown Chicago before heading further to the Illinois River and further inland waterways.

This route has a high technical interest as it includes such aspects of boating as urban navigation, bridges with movable spans, commercial navigation, the large navigation lock, and the man-made waterway connecting the Great Lakes and Mississippi basins. According to AGLCA, the air draft of a vessel plays a vital role for navigation through the Chicago River downtown area. Those vessels which are not able to pass under the downtown bridges have to follow the alternative Calumet-Sag route.

The Chicago Great Loop Route Navigation Details

Boats coming to Chicago from Lake Michigan should start their downtown route from the Chicago Harbor Lock. This lock acts as the dividing point between the Lake Michigan basin and the Chicago River. Then, boats continue their journey via the branches of the Chicago River to the Chicago Sanitary and Ship Canal and further to the Illinois Waterway.

The Chicago Sanitary and Ship Canal is an artificial waterway which links the Chicago and Des Plaines rivers. It provides a vital aquatic link between the watersheds of Lake Michigan and the Mississippi River.

This is not just a beautiful city tour. Since the waterway belongs to the operating system of navigational facilities, Loopers need to be ready for joint use of the channel by commercial vessels and adherence to navigation regulations.

Chicago Harbor Lock

The Chicago Harbor Lock is the entrance into the Chicago River from Lake Michigan. According to USACE, the lock chamber is 600 feet long, 80 feet wide, and 22 feet deep.

The lock sees plenty of traffic. As reported by USACE, more than 9,859 lockages were completed during the 2025 boating season for the movement of over 72,000 commercial, recreational, and government vessels. The 2026 boating season was opened on April 15 after off-season maintenance.

Due to the heavy traffic, please check the current USACE navigation notifications before you reach the lock.

Cruising the Chicago River

The Chicago River is the most exciting stretch of the Great Loop in any urban area.

According to USACE, there is a 2.97-mile navigation channel between Michigan Avenue and North Avenue.

The main problem that Loopers encounter when navigating the Chicago River in downtown Chicago is the question of clearance. According to AGLCA, the boats navigating the Chicago River should clear the 17-foot bridges. This clearance is referred to as air draft, which means that the boat's height above the water should include all antennas and other equipment.

In case your boat is not capable of clearing the required downtown clearance, you will have to use the Calumet-Sag Canal south of Chicago instead of the downtown Chicago River route.

Chicago Sanitary and Ship Canal

Following the section of the Chicago River, the course proceeds through the Chicago Sanitary and Ship Canal. This waterway opened in 1900, and its purpose was to reverse the Chicago River flow to protect the Lake Michigan water supply from being contaminated by the sewerage and provide a navigational connection.

At present, the canal is one of the key commercial routes in Chicago. Besides, it belongs to the connecting channels between the watersheds of the Great Lakes and Mississippi River basins.

The canal also includes the Chicago Sanitary and Ship Canal Dispersal Barriers, which serve as barriers to prevent the transfer of alien aquatic species between the watersheds. Electric barriers are situated near Romeoville City.

Navigating the Fish Dispersal Barrier Area

There are certain navigation rules for the dispersal barrier area. In accordance with the US Army Corps of Engineers, there is a regulated navigation area near the barriers in the Romeoville area. To navigate this section of the waterway, a vessel should meet all applicable requirements.

It is an important aspect to review NTNIs of USACE before departure. There can be some restrictions on navigation due to the testing, maintenance, and any other work. For instance, USACE published 2026 notices concerning closures and testing in the barrier area.

Don't assume that the published cruise schedule still applies.

Lockport Lock

Further downstream, Loopers will find themselves at Lockport Lock and Dam, which is an important point in the Illinois Waterway System. This lock has a width of 110 feet and a length of 600 feet with an average lift of 39 feet.

There have been major repairs at Lockport in 2026. The lock was closed temporarily by the USACE from March 31 to May 19 due to some important repairs. The lock was reopened fully to navigation traffic on May 19, 2026.

This example proves why up-to-date navigation notices are important in planning a Great Loop voyage.

Chicago Route Planning and Safety

Before going into the Chicago waterways, check the size of your boat and the latest navigational information.

In particular,

• Air draft, particularly for the route along the downtown Chicago River
• Bridge opening schedule
• Chicago Harbor Lock condition
• Lockport Lock condition
• USACE navigation advisories
• Commercial traffic
• The latest electronic navigational charts
• Weather and visibility conditions
• The draft and beam of your boat
• Speed limits and wake regulations

Especially pay attention to commercial traffic along the Chicago Sanitary and Ship Canal and the Illinois Waterway. Keep a proper lookout, stay in touch, and allow sufficient room to the tows and barges.

Frequently Asked Questions

Do Great Loop boats go through downtown Chicago?

Yes, assuming the boat can comply with the applicable bridge clearance. AGLCA notes that boats on the Chicago River through downtown need to be able to clear 17-foot bridges. Boats unable to do this may take the Calumet-Sag route.

Where does the Chicago River Great Loop start?

For those coming from Lake Michigan, the entry point into the Chicago River is the Chicago Harbor Lock, located near Navy Pier.

What is the Chicago Sanitary and Ship Canal?

This is an artificial waterway connecting the Chicago River with the Des Plaines River and hence the Mississippi River system. It was opened in 1900 as part of the great water engineering works in Chicago.

What if my boat is too tall for the Chicago River?

If your boat is not able to comply with the bridge clearances in the downtown area, you should take the Calumet-Sag Canal route south of Chicago.

Is Lockport Lock open now?

Yes. According to USACE, Lockport Lock was opened for navigation on May 19, 2026 after critical repair works.

Why are there electrical barriers in the Chicago Sanitary and Ship Canal?

The electrical barriers are a part of the system controlling the movements of aquatic nuisance-species from the Mississippi River basin into the Great Lakes basin.

Conclusion

This segment of the Great Loop around Chicago River and its channel to Lake Michigan is undoubtedly unique, combining Lake Michigan access, Chicago downtown bridges, urban navigation, commercial waterways, navigation locks, and man-made water connection of two major watersheds.

The way to success in navigation is in preparation. Make sure that you know your air draft, have knowledge of your route choices, consult recent USACE notice, learn the lock conditions, and use recent navigation charts instead of old cruises books.

GPS Nautical Charts offers you navigation chart resources for the Great Loop route planning.