| County Line Road (Barrington Hills), Main Street (Barrington) | |
 Lake Cook Road from the Des Plaines River Trail | |
| Part of | CR A50 |
|---|---|
| Maintained by | the Illinois Department of Transportation, the Cook County Highway Department, and the McHenry County Division of Transportation |
| Length | 25.5 mi (41.0 km)[1] |
| Location | Lake, Cook, McHenry, Kane counties |
| West end |  IL 62 (Algonquin Road) in Algonquin |
| East end | Sheridan Road in Highland Park and Glencoe |
Lake Cook Road (alternatively referred to as County Line Road or Main Street in some areas) is a major east–west highway in Cook, Lake, McHenry, and Kane Counties in Illinois. For much of its length, it marks the border between Cook and Lake Counties, hence the name of the road. In its western stretch, it marks the border between McHenry and Cook Counties, and further west, McHenry and Kane Counties. The road is approximately 25.5 miles (41.0 km) in length, from its western terminus at Illinois Route 62 in Algonquin to its eastern terminus at Sheridan Road in Highland Park and Glencoe, near Lake Michigan. The road is notable for its cross-section of Chicago's northern suburbs, balancing densely developed commercial, industrial, and residential land uses, with open space areas such as forest preserves, parks, golf courses, creeks, rivers, gardens, and Lake Michigan.
- ^ Google Maps estimate.