By Zack Colman - 12/04/12 04:51 PM EST
Domestic crude oil production in September hit the highest monthly output since 1998, according to the U.S. Energy Information Administration (EIA).
Oil production yielded 6.5 million barrels per day in September, EIA said. Daily production increased by 900,000 barrels daily compared with last September.
EIA credited horizontal drilling combined with hydraulic fracturing, popularly known as "fracking," for driving the production growth.
Lawmakers have lauded fracking for ushering in an era of greater energy self-sufficiency. The method helped turn the U.S. into a net oil exporter in 2011 for the first time since 1949.
The practice has fueled energy booms in states such as North Dakota and Texas, which have sizable deposits of shale oil and gas. EIA said those two states experienced the largest jumps in oil production.
Oil drilling featured prominently during the 2012 campaign, with the topic occupying a significant portion of the energy debate in the White House race.
President Obama has bucked Republican calls to open more federal lands to drilling while pointing to oil-production levels that exceed those during former President George W. Bush’s administration.
In debates with Mitt Romney, Obama often touted oil-production figures during his first term as a way to brandish his fossil fuel credentials.
But Republicans say most of that activity has come from production gains on private and state lands and argue there are more hydrocarbons on federal lands waiting to be tapped.