Welcome to Knife River of Portland,OR -Who is Knife River Corporation? Knife River is one of the top 10 aggregate, ready-mix and sand and gravel producers in the nation. At peak construction season we employ more than 5,000 men and women who have been widely recognized for their superior customer service. We are sitting on a foundation of more than 1.1 billion tons of aggregate and provide a wide variety of products and services necessary for building America's infrastructure. -Since purchasing the first aggregate company in 1992, Knife River has become one of the fastest-growing aggregate and construction companies in the central, southern and western United States. We have acquired nearly 70 companies located in 14 states and are licensed to perform work in many more.- Our core business lines include aggregate, asphalt, ready-mix concrete, liquid asphalt and cement.