Karl P. Biller was a bridge designer on the Historical Columbia River Highway. Working under Oregon state bridge engineer Charles Purcell, Billner designed many of the signature spans along the Historical Highway. Billner's designs during the early years of highway construction helped influence the future of bridge design in Oregon.

Bridal Veil Creek Bridge (Multnomah County, Oregon)
Engineer, 1914
Girder bridge over Bridal Veil Creek on Historical Columbia River Highway (HWY 100) in Bridal Veil
Open to traffic

Eagle Creek Bridge (Multnomah County, Oregon)
Engineer, 1914
Concrete arch bridge over Eagle Creek on Service Road
Open to traffic

East Multnomah Falls Viaduct (Multnomah County, Oregon)
Design Engineer, 1914
Bridge over Rocky terrain along railroad tracks on Historical Columbia River Highway
Open to traffic

Horsetail Creek Bridge (Multnomah County, Oregon)
Engineer, 1914
Slab bridge over Horsetail Creek on Historical Columbia River Highway
Open to traffic

Latourell Creek Bridge (Multnomah County, Oregon)
Design Engineer, 1914
Concrete arch bridge over Latourell Creek on Historical Columbia River Highway
Open to traffic

McCord Creek Bridge (Multnomah County, Oregon)
Built 1915
Lost Concrete deck girder bridge over McCord Creek on Historic Columbia River Highway (US 30)
Replaced by new bridge in 1997

Multnomah Creek Bridge (Multnomah County, Oregon)
Engineer, 1914
Concrete arch bridge over Multnomah Creek on Historical Columbia River Highway
Open to traffic

Oneonta Creek Bridge (Multnomah County, Oregon)
Engineer, 1914
Concrete beam bridge over Oneonta Creek on Historical Columbia River Highway
Open to traffic

Shepperds Dell Bridge (Multnomah County, Oregon)
Engineer, 1914
Concrete arch bridge over Shepperds Dell on Historical Columbia River Highway
Open to traffic

Stark Steet Bridge (Multnomah County, Oregon)
Design Engineer, 1915
Concrete arch bridge over an unnamed draw on Stark Steet
Open to traffic

Stark Street Bridge (Multnomah County, Oregon)
Engineer, 1914
Truss bridge over Sandy River on Stark Street
Open to traffic

Wahkeena Creek Bridge (Multnomah County, Oregon)
Engineer, 1914
Slab bridge over Wahkeena Creek (Gordon Creek) on Historical Columbia River Highway
Open to traffic

West Multnomah Falls Viaduct (Multnomah County, Oregon)
Design Engineer, 1914
Bridge over rocky terrain along railroad tracks on Historical Columbia River Highway
Open to traffic