When did the United States start to import oil?

The United States began importing oil in the mid-19th century, with the first significant imports occurring in the 1850s. The discovery of oil in Pennsylvania in 1859 marked the start of the American oil industry, but domestic production couldn't meet growing demand, leading to imports primarily from places like Venezuela and later the Middle East. By the early 20th century, oil had become a crucial part of the U.S. economy, prompting increased imports to satisfy industrial and military needs.