The US became the world's biggest economy in the late 1890s. So how did we become the largest economy? Stealing a large landmass blessed with abundant resources and fertile arable land. Growing the population immensely via high birth rates and immigration. Industrious population and business friendly laws helped. But it was mostly OIL. The US was the saudi arabia of oil for nearly 100 years from mid 1800s to ww2. Standard Oil became the largest company in the world for a reason. We had a ridiculous amount of oil and we exploited it. Oil was discovered in the 1850s and it helped the american economy become the largest in the world.