The Eagle Ford tops the list of the 100 largest oil fields in the country, with Eagleville overtaking Alaska’s Prudhoe Bay for the number one spot.

The Energy Information Administration (EIA) made it official, reporting that the shale oil boom has contributed significantly to the U.S. oil and gas reserves as production numbers skyrocketed between 2008-2013.

Related: EIA: Texas is Largest Producer of Shale Natural Gas

A new report released in late March and based on the latest data from 2013, shows the top 100 oil fields accounted for 20.6 billion barrels of crude oil and lease condensate proved reserves, which was 56% of the U.S. total.  The top 100 gas fields provided 68% of U.S gas reserves in 2013 with 239.7 trillion cubic feet of total natural gas proved reserves.

At the top of the list are two fields from the Eagle Ford Shale Play in Texas, Eagleville and Briscoe Ranch. Eagleville spans 14 counties in South Texas and is the country’s largest oil field, which produced 238,050 million barrels in 2013. These fields also made the top 20 list for natural gas with Eagleville coming in at 12 and and Briscoe Ranch at #13. Just a few short years before, these Eagle Ford fields did not even appear in the top 100.

Read full report at eia.gov