Robert P. Astorino, the county executive and a vocal supporter of Indian Point, which is in the village of Buchanan, said more than $4 million enters the county’s coffers every year from the plant, representing nearly 1 percent of the tax base. “No one from the governor’s office had the common courtesy to call the county affected by this,” Mr. Astorino, a Republican, said. “So we’re all trying to figure out what will happen in the future and the costs of this potential closure. There are enormous economic consequences to something like this.”

Perhaps no single entity will suffer the financial effects of the shutdown more than Hendrick Hudson schools, a district with 2,400 students that draws from parts of a half-dozen towns and villages near the plant. The superintendent, Joseph E. Hochreiter, said taxes from the company that owns Indian Point, Entergy, made up one-third of the district’s $75.8 million operating budget annually.

“We’ve enjoyed some of the lowest property tax increases of any school district in Westchester County and that has made this a very appealing community to move to and stay in,” he said. “Entergy plays a major, major role in keeping taxes down. If they are not operating at the capacity that we’re accustomed to, we are going to have budget deficits.”

Converting Indian Point’s property to another use — whether residential or commercial — may not be possible, given the environmental history of the 240-acre site.

Still, after years of hand-wringing over the potential for a catastrophe, many residents said they would be happy to have a nuclear-free county. Opponents of the plant had seized on the Sept. 11 terror attacks and, later, the Fukushima Daiichi nuclear disaster in Japan to galvanize support for shutting Indian Point.