“Close” is said to count only in horseshoes and hand-grenades, but now the city’s historic preservationists and not-in-my-backyard crowd are trying to add landmark status to that elite list. On the Upper East Side, a neighborhood that lately is not taking change lightly, some residents are petitioning the Landmarks Commission to expand the boundaries of one of the city’s largest historic districts to disrupt planned residential developments.

Neighbors are particularly annoyed by a plan from Davis Development to build an 18-story condominium at the current site of the Kean House on Lexington Avenue, just a few yards from the existing boundary of the Upper East Side Historic District. The Landmarks Commission dismissed a previous attempt to landmark the Kean House, a squat, non-descript building at 65th Street, determining it did not meet the criteria for landmark status.

In Chelsea, residents are in an uproar about another as-of-right plan by the Tishman Realty Corporation to build a 20-story hotel condominium on West 15th Street on a site they bundled together with air rights from Xavier High School. The lot falls just one block to the west of the Ladies Mile historic district.

In May, the Landmarks Commission extended the NoHo historic district, and now preservationists are also trying to expand boundaries of the Carnegie Hill historic district and another in Douglaston, Queens. Of the city’s 92 historic districts, there have been 13 extensions to those districts.

The location of boundaries of a historic district can be worth tens of millions of dollars. On the non-landmarked side, developers are held in check merely by the city’s already Byzantine and restrictive local zoning laws. In a historic district, they must, on top of the other restrictions, gain approval from the Landmarks Commission, which can send developers back the drawing board if they don’t think the design appropriate for the neighborhood.

That can be costly. Just ask St. Vincent’s Hospital and the Rudin Family or developer Aby Rosen, who recently had their grand plans for Greenwich Village and the Upper East Side blocked by Landmarks.

With the city adding thousands of housing units a year, and entire neighborhoods being remade, preservationists and neighbors are now seeing the historic district borders as negotiable. It’s just the latest example of their attempt to use the city’s Landmarks law to strangle dynamic change in New York, blocking property owners from building on properties they have bought and paid for. The effect would be a city with fewer housing units, fewer construction jobs, and a smaller tax base.

If the Landmarks Commission had determined that neighboring sites belonged in the historic district, they would have included the neighboring sites in the first place. Just because a new, gleaming condominium might cast a shadow into a historic district doesn’t mean it should be disallowed. Close, but no cigar.