Five years ago few people had ever heard of the Eagle Ford. Today, it's one of the largest oilfields in the United States. Yet despite the run, the formation is still in its infancy. 

Since production began in 2008, the South Texas play has produced some truly spectacular statistics. Here are the top seven most remarkable numbers from the Eagle Ford. 

1) 20,000 square miles
The Eagle Ford shale play swoops across the Lone Star State from the Mexican border up through East Texas. At 20,000 square miles in size, the field is one of the largest oil and gas formations in the continental United States.

2) 900,000 barrels per day
The Eagle Ford expansion has occurred at a breathtaking pace. In 2008, output from the entire field consisted of a single Petrohawk well -- now owned by BHP Billiton (BBL) -- which produced 358 barrels of oil equivalent per day, or boepd.

Today, BHP's Eagle Ford production has exceeded 100,000 boepd. And according to Deutsche Bank, the play should contribute more than 15% of the mining giant's free cash flow over the next seven years.

In aggregate, total Eagle Ford output averages about 900,000 boepd.And based on projections by Benteck Energy, production is expected to surpass 1.5 million boepd by 2018.

3) 10 billion barrels
The Eagle Ford holds between 7 billion and 10 billion recoverable barrels of oil based on estimates provided by the United States Geological Survey. If accurate, that would make the play the largest oil reserve in the lower 48 states. 

4) $6 million per well
However, the horizontal drilling and hydraulic fracturing techniques needed to unlock the Eagle Ford's bounty aren't cheap. The typical well will set you back between $5 million and $7 million, making it one of the more expensive fields in North America.

Fortunately those costs are coming down. Over the past two years, Forest Oil's (NYSE: FST) average well completion costs in the Eagle Ford have fallen 27% to $5.8 million per well. When you multiply that figure across the 30 net wells the company plans to drill next year, you get $66 million in annual cost savings. That's a substantial figure for a company with a $500 million market capitalization. 

5) $28 billion in capital spending
The Eagle Ford has become the top destination for energy companies to park their capital. According to Wood Mackenzie, the oil industry will spend $28 billion in capital expenditures developing acreage this year.

6) $113,000 per flowing barrel
All of this spending is pushing up the valuations for Eagle Ford assets. In November, Devon Energy (DVN -0.63%) acquired 82,000 net acres in the area from privately held GeoSouthern. The price tag on this transaction: $6 billion, or $113,000 per flowing barrel. That's steep relative to most oil and gas deals but roughly in line with other shale acquisitions. The high valuations show just how optimistic the industry is on the Eagle Ford.

7) 116,000 jobs
According to a University of Texas at San Antonio study, the Eagle Ford has created 116,000 direct and indirect jobs. The report also estimates that the field generated $2.2 billion in tax revenue for the state and local governments last year.

Foolish bottom line
What's truly remarkable about the Eagle Ford is that we might still be in the early innings of the play's expansion. So far the Texas Railroad Commission has issued slightly more than 5,400 well permits. But the UTSA's study calculates that there's room for a total of 24,000 drilling locations. This means that the Eagle Ford may be less than one-quarter developed and suggests that there is still plenty of opportunity for investors.