Production in January fell by 56,000 barrels per day to 9.179 million bpd, according to monthly data from the US Energy Information Administration released on Thursday.
The level was the lowest since October 2014, according to the EIA's data.
Gulf of Mexico output fell 18,000 bpd while North Dakota's oil output was down 32,000 bpd from December levels. At the same time, production in Texas rose 25,000 bpd. Production for December was revised downward by an additional 27,000 bpd to 9.235 million bpd, according to the EIA.
The data, which is released two months after the fact, is considered to be one of the most accurate benchmarks of US oil production, and is more reliable than weekly data.
It is a critical component of estimates by analysts and traders who are trying to gauge the shale boom's response to sustained low prices, which have lasted nearly two years.
Shale producers have proved more resilient to low prices than the market initially anticipated, as producers last month began to lock in crude hedges at just $45 a barrel, indicating that their break-even prices have gotten even lower.