The United States had 94 operating commercial nuclear reactors at 54 plants in 28 states as of March 2026, with combined net summer capacity of 98,441 megawatts, according to the US Energy Information Administration.

The fleet is mature. The average reactor is about 44 years old. The oldest operating unit, Nine Mile Point Unit 1 in New York, entered commercial service in December 1969, while the newest, Vogtle Unit 4 in Georgia, began commercial operation in April 2024. Even so, nuclear plants posted an average capacity factor of 91 percent in 2025, higher than any other type of power plant.

Plant layouts vary widely. Nineteen plants have a single reactor, 31 have two, three have three reactors and one has four. Georgia's Plant Vogtle is the largest US plant, with four reactors totaling 4,530 megawatts. The largest single reactor is at Grand Gulf in Mississippi at about 1,400 megawatts, while the two units at Prairie Island in Minnesota are the smallest, at about 520 megawatts each.

Illinois leads the states. At the end of 2025 it held about 11,592 megawatts of nuclear capacity across 11 reactors at six plants, the most of any state.

The EIA map that accompanies the data shows plant locations concentrated in the eastern half of the country, with clusters along the Southeast coast, in the Midwest and across the Mid-Atlantic. The map reflects plant locations as of June 2023, while the fleet statistics are current to March 2026.

Source: US Energy Information Administration -- https://www.eia.gov/energyexplained/nuclear/us-nuclear-industry.php