title: American River
context: The North Fork is the longest tributary of the American River, at 88 miles (142km).[6] It begins at an elevation of about 7,900 feet (2,400m) near Lake Tahoe in Placer County at Mountain Meadow Lake, just northeast of Granite Chief and immediately due west of Squaw Valley Ski Resort. It flows westward through remote wilderness areas.
question: What is the longest fork in the American River?
answers: North Fork