 The freeway then continues through the city of Shasta Lake, intersecting SR 151, before crossing over Shasta Lake on a causeway and climbing up to near the foot of Mount Shasta.In Siskiyou County, I-5 passes through Dunsmuir before intersecting SR 89 near Lake Siskiyou and entering the city of Mount Shasta.North of here, US 97 intersects I-5 in Weed, providing access to Klamath Falls, Oregon.