While the U.S. census provides a close approximation of the year-round population of Martha’s Vineyard, the more porous summer population has been at best an educated guess and at worst a projection untethered from reality. 

Numbers published in various publications have been as high as 200,000 people here at any given time, while others have pitched more moderate calculations. The Gazette itself advertises a rather exact 105,624 summer population on its front page, though the methodology behind that isn’t quite clear. 

To try and get a more accurate take on the elusive number, one that will always require a bit of conjecture, the Martha’s Vineyard Commission went to work. Last week, it came up with its best estimate: 94,650. 

“People have always taken a stab at it,” said Alex Elvin, the research and communications manager at the commission who led the quest to find the number. “People based on what they see. I think the data that we found generally indicates it’s less than people often think.” 

— Courtesy of MVC

To arrive at the estimate, the commission took the 2020 census, which puts the year-round population at 20,530, then added the expected number of overnight guests and seasonal residents, plus projections about the number of day-trippers on any given day. 

The result is what Mr. Elvin expects could be the largest number of people on the Island on a busy summer day. 

“It’s the most we would reasonably expect there to be in August,” he said. 

The commission made estimates on the summer population in the past, though Mr. Elvin said the methods to arrive at those figures were hazy. The last MVC guess in 2018 put the summer population at 89,231. 

The new methodology looked at the total number of bedrooms on the Island via assessor data. For seasonal residents, the commission applied the occupancy rate for each Island property based on the average household size in the county where the homeowner primarily received mail. 

The commission then added up estimates for guests and tenants of seasonal residents, overnight guests at hotels, the family campground, boats and the homeless population. 

The final and most slippery estimate in the summer population equation was for day-trippers who flock to the Island aboard boats from Nantucket, the Cape, New Bedford and Rhode Island. The Steamship Authority doesn’t track length of stay for walk-on passengers, but about 50 per cent of the 23,416 cars parked in the boat line’s Falmouth lots in August 2023 did not stay overnight, giving a reference point for peak day-trippers. 

Based on this number, and other extrapolating, the commission estimated about 3,219 passengers a day were day-trippers. Other ferry providers, which don’t offer vehicle ferries, were expected to be almost exclusively daytrippers. 

Adding these numbers arrived at the 94,651 figure — nearly five times the year-round population.

While crunching the numbers, the commission found some other fun facts. The Island boasts seasonal homeowners from nearly every state; only Nebraska or North Dakota residents have not deemed the Vineyard second home material. 

Counting the various factions has proved difficult over the years. — Larry Glick

Massachusetts residents, perhaps expectedly, make up the majority of seasonal homeowners here, with 2,799 properties owned by people with non-Island, Bay State addresses. New Yorkers own the second most properties at 1,147, and Connecticut residents followed with 727. 

Nearly 45 people with mailing addresses in 11 foreign countries also own property here, with the largest contingent (19) coming from the United Kingdom. 

The new assessment could also serve a practical use above and beyond trivia night. Mr. Elvin said nonprofits and other organizations could be able to use the data when seeking grants. 

“I think a lot of nonprofits, when they are asking for money and grants, it’s important to say how large your population actually is,” he said. “We hope that people use it.”