Business Loop I-5 - Castle Rock
The lone Business Route for Interstate 5 in Washington follows Huntington Avenue west between Exits 48 and 49. The southern two thirds of the 2.4 mile long loop are locally maintained. North from A Street and the Castle Rock city center, Business Loop I-5 coincides with Washington State Route 411. SR 411 north ends at I-5 opposite from SR 504 south.
North
Business Loop I-5 commences northbound along Huntington Avenue from the diamond interchange at Exit 48.
07/20/23
Replaced guide sign from I-5 north at Exit 48 for Business Loop I-5 north to the Castle Rock city center.
09/02/06
Huntington Avenue stems west from the intersection of Bond Road and Kalmbach Road in southeast Castle Rock into the exchange with I-5. Bond Road is the east side frontage road for Interstate 5.
07/20/23
09/02/06
Business Loop I-5 (Huntington Avenue) north at the southbound entrance ramp to Interstate 5.
07/20/23
09/02/06
Pleasant Hill Road, the historic alignment of U.S. 99, runs south from Huntington Avenue to Pleasant Hill. Business Loop I-5 spans the BNSF Railroad beyond the intersection.
07/20/23
A sign for Business Loop I-5 stands along Huntington Avenue northbound between Larson Lane SW and Lions Pride Park along the Cowlitz River.
07/20/23
Castle Rock (elevation 190 feet) rises along the Cowlitz River alongside Huntington Avenue north at Buland Drive.
07/20/23
SR 411 north on A Street at the turn onto Business Loop I-5 (Huntington Avenue).
07/20/23
SR 411 is unmarked along Huntington Avenue north where the route combines with Business Loop I-5. SR 411 south follows A Street west across the Cowlitz River to Westside Highway.
07/20/23
North
Business Loop I-5/SR 411 proceed north one block along Huntington Avenue to Cowlitz Street. Cowlitz Street flows west into the Castle Rock business district and continues east with two-way traffic to Powell Road..
07/20/23
Business Loop I-5 trailblazer preceding Mallory Street along Huntington Avenue north.
07/20/23
Business Loop I-5/SR 411 (Huntington Avenue) angle northeast across the BNSF Railroad ahead of the diamond interchange (Exit 49) with Interstate 5.
07/20/23
Washington State Route 504 (Mount Saint Helens Way) begins east from the exchange joining Business Loop I-5/SR 411 with Interstate 5. The scenic highway spurs 51.76 miles east to Mount Saint Helens National Volcanic Monument.
07/20/23
South
SR 411 begins south alongside Business Loop I-5 from the diamond interchange (Exit 49) joining Interstate 5 with SR 504 east and Huntington Avenue.
07/20/23
Huntington Avenue arcs south across a BNSF Railroad to the Castle Rock city center.
07/20/23
Front Avenue branches south from Huntington Avenue at Gateway Park along the Cowlitz River. Both streets lead south to Downtown Castle Rock.
07/20/23
Cowlitz Street extends west from Powell Road into the Castle Rock business district at Huntington Avenue.
07/20/23
SR 411 separates from Business Loop I-5 (Huntington Avenue) at A Street. Signage for the continuation of the route south to Beacon Hill and Longview was missing in 2023/24.
07/20/23
South
Business Loop I-5 (Huntington Avenue) passes Castle Rock (elevation 190 feet) ahead of Lions Pride Park along the adjacent Cowlitz River.
07/20/23
Business Loop I-5 (Huntington Avenue) spans a BNSF Railroad ahead of Pleasant Hill Road (Old U.S. 99) and the diamond interchange (Exit 48) with Interstate 5.
07/20/23
Huntington Avenue ties into the intersection of Bond Road and Kalmbach Road east beyond the exchange with Interstate 5 in south Castle Rock.
07/20/23
Photo Credits:
- Brent Ivy: 07/20/23
- AARoads: 09/02/06
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Page Updated Thursday September 18, 2025.