The agency said inventories climbed to 371.7 million barrels. Economists had expected a jump of 2.9 million barrels to 372 million.
Supplies of crude oil remain "well above the upper limit of the average range for this time of year," the agency said in a report issued late Wednesday.
The EIA said supplies of distillate fuels, which include home heating oil, dropped by 1 million barrels to 129.6 million barrels. Inventories of distillate fuels are in the lower half of the average range for this time of year, the agency said.
Stockpiles of gasoline rose by 1.7 million barrels to 234 million barrels this week, but remain in the upper limit of the average range for this time of year.
In the week ending Monday, the national average price for a gallon of unleaded gasoline rose for the seventh consecutive week, climbing to $3.538 per gallon, up 18.1 cents from the previous week. The average price is 5.6 cents above the same week a year earlier, the EIA said.