API said U.S. crude oil production increased 15.6 percent year-on-year last month to average 8.3 million barrels per day, the highest level for June in 28 years.
Total oil imports, meanwhile, declined 5.7 percent from the previous year to average 9.2 million barrels per day, which API said was the lowest level for June since 1993.
API Chief Economist John Felmy said the data show the United States is getting closer to energy independence.
"Increased U.S. production in recent years has provided an almost barrel-for-barrel counterweight to various disruptions in global supply from overseas," he said in a statement.
In terms of the strength of the domestic economy, API said total U.S. petroleum deliveries, an indication of demand, increased 1.5 percent year-on-year, with demand during the second quarter increasing 1.5 percent when compared to the same time last year.
Production for gasoline, which accounts for much of the petroleum used in the United States, was at its second-highest level ever recorded in June. Demand for gasoline increased 4 percent in June year-on-year.