Costain Group PLC provides smart infrastructure solutions for the energy, water, transportation, and defense markets in the United Kingdom. The company operates through two segments, Transportation and Natural Resources. The Transportation segment operates in the road, rail, and integrated transport markets. The Natural Resources segment operates in the water, energy, and defense markets. It offers future shaping strategic consultancy, consultancy and advisory, digital technology, asset optimization, and complex program delivery solutions and services. The company was founded in 1865 and is headquartered in Maidenhead, the United Kingdom.