Great Loop Lock Reference

Chain of Rocks Lock 27

Reviewed planning reference for lock approach, communications, and float-plan preparation.

Upper Mississippi River / Chain of Rocks Canal

Chain of Rocks Lock 27

Granite City, IL

Latitude / Longitude38.755500
-90.176000

PhoneNot listed

VHF Channel12

Operating AuthorityNot listed

Last ReviewedNot listed

Lock Location

Zoomed-in location for this Great Loop lock reference.

About This Lock

Segment: Upper Mississippi River / Chain of Rocks Canal. Route status: core inland-river route. Approximate coordinate. USACE identifies Lock 27 near the Chain of Rocks Canal; verify phone/VHF before transit. Source: https://www.mvs.usace.army.mil/Missions/Navigation/Locks-and-Dams/Lock-Dam-27/

Before You Arrive

Fenders ready
Lines ready
Crew briefed
PFDs on deck
Radio on correct channel
Call / monitor lock
Check current notices

Plan With FPW

Add lock planning context to your route and account for lock delays in your float plan.

Plan a Float Plan

Official Source

Official source

Open official source

Navigation Safety Note

This page is a planning reference, not a substitute for official notices, charts, lockmaster instructions, or current local conditions. Always confirm lock status, operating hours, closures, restrictions, and instructions with the official authority before arrival.