Is One Dalton the last 700-foot tower in Boston for a generation?

At some point during the next 12 months or so, the 742-foot Four Seasons Hotel & Private Residences One Dalton Street in western Back Bay will top out and open.

That milestone will very likely mark the last time for a generation that Boston will see the completion of a tower of at least 700 feet.

That is not because of a lack of demand for the hotel rooms, the housing, and the offices that would go up in such a tower. Those sectors are notoriously tight in Boston, especially the first two.

Nor is it because of a lack of interest from developers and their allies. Boston provides some of the best returns on investment in real estate in the nation, whatever the construction costs.

Nor is it necessarily a lack of political will on the part of many elected officials, some of whom, including Mayor Marty Walsh, have thrown vocal support behind projects such as a conversion of the Winthrop Square Garage into a high-rise condo-and-office spire.

No, One Dalton likely marks literally a high-water mark for Boston development because the city, a compact one whatever its expansions over the centuries, is running out of sites for such tall towers.

The sites have to have a few things going for them going in.

For one, they can’t be within areas where the Federal Aviation Administration would view a tall tower as a nuisance—or worse—for Logan Airport.

For another, they can’t be in a location where a tall tower would most assuredly cast shadows on Boston landmarks. Witness the recent kerfuffle regarding new towers over and around Back Bay Station and the Winthrop Square Garage affair (and the tallest of the Back Bay Station towers is not even 370 feet).

And, finally, the sites can’t be in spots where neighbors might deem a tall tower intrusive or out of scale (see: saga, Harbor Garage redevelopment).

So that leaves a few sites in the West End and maybe some out along the tail of Boston’s so-called High Spine in western Back Bay. Even then, though, plans, lawsuits, re-planning, re-litigating, etc., could mean years between a 700-foot tower’s proposal and its completion.

When the 685-foot Millennium Tower opened in 2016 in Downtown Crossing, after years of squabbling about the site and about the design of the new project, it was the tallest new building in Boston since the 790-foot 200 Clarendon in 1976 and the first tower over 600 feet since the 614-foot Federal Reserve building opened the same year.

In other words, the first in at least a generation.

• Back Bay Station towers developer to pay $6 million to mitigate shadow concerns [Curbed Boston]
• Just how high can developers get in Boston? [Curbed Boston]
• Boston’s 10 tallest buildings by 2020, mapped [Curbed Boston]
• Winthrop Square tower renderings show a still-sizable spire, whatever the shrinkage [Curbed Boston]
• Boston Harbor Garage redevelopment back on—sort of [Curbed Boston]
• Millennium Tower: The ultimate timeline for Boston’s tallest residential building [Curbed Boston]
• Boston reclamation: The 5 most significant infills in the city’s history [Curbed Boston]