The company defined the resource by spending roughly $3.5 million in under two years and drilling 13,919 metres of core, it said.
This resulted in an inferred gold resource of 4.34 million tonnes grading 3.53 grams per tonne (g/t), at a 1.0 g/t cut off, for 492,000 ounces of gold.
With a higher cutoff grade of 6.0 g/t, the property hosts an inferred gold resource of 249,000 ounces with an average grade of 9.94 g/t gold.
BonTerra also said it believes there is potential for expansion with further drilling, as the existing resource is open to the northeast, southwest and down dip.
The mineral resource estimate, done by Snowden Mining, includes the results of 12,543 metres of core drilling completed on the property in 2011.
BonTerra's Rivage Zone, where more than 5,900 metres of drilling has taken place this year, was not included in the estimate, which is constrained by geologic domains consisting of ten vein structures.
The company said it plans to file a complete technical report on SEDAR within 45 days.
The Urban-Barry gold camp hosts two other gold projects with NI 43-101 compliant resources, known as the Windfall Lake and the Barry deposit.
"BonTerra is very proud to have received such a great first ever resource estimate from Snowden for our gold property," said president Navjit Dhaliwal.
"It is not common for a junior company like BonTerra Resources to develop an asset of such high potential in such a short period of time.
"We feel this resource estimate completed by Snowden solidifies BonTerra as a leading junior gold explorer in Quebec's Abitibi Greenstone Belt. This also speaks volumes about the high quality of the Property as well as all of our team in Vancouver and Val d'Or."
The company said that highlights of its 2012 drilling at Rivage include 73.82 g/t gold over 3.0 metres in hole BA-12-10, which included 1.0 metre of 220.0 g/t gold.
This drill hole at the Rivage was collared around 120 metres from the Rivage discovery outcrop. A chip sample taken from this outcrop in the fall of 2011 assayed 204 g/t gold.
The Eastern Extension property is situated roughly 170 kilometres northeast of Val d'Or, Quebec in the Abitibi Greenstone Belt.
Shares of BonTerra rose more than 9 per cent Wednesday afternoon, to 12 cents.