One of the ways that the Lewis and Clark expedition influenced economic growth in the United States during the 1800s was by opening up new trade routes. The expedition's exploration of the western territories allowed for the discovery of valuable resources such as furs, timber, and minerals. This led to an increase in trade with Native American tribes and European countries, which helped to boost the economy. Another way that the Lewis and Clark expedition influenced economic growth was by promoting westward expansion. The expedition's findings and reports helped to spark interest in the western territories, leading to an influx of settlers, businesses, and investments. This expansion led to the development of new industries, such as mining and agriculture, which further contributed to the country's economic growth.