A new study named desirable seaside enclave Nantucket the No. 1 most expensive ZIP code in New England and No. 30 nationwide. Notably, Boston dropped out of the top 100 most expensive U.S. ZIPs for the first time since 2016.

Real estate research company PropertyShark ranked U.S. ZIP codes based on registered residential transactions closed between Jan. 1 and Sept. 30. States with non-disclosure rules including Montana, Texas, Utah and Wyoming were excluded due to lack of data.

Atherton, California took the No. 1 spot nationwide and broke the eight-figure median sales price benchmark with a $10.73 million median residential sales price.

In New England, Nantucket’s median sales price grew 44% year-over-year, hitting $3.6 million. Other Massachusetts ZIPs that ranked included Chilmark (No. 35) at $3.4 million, Edgartown (No. 87) at $2.36 million, Weston (No. 85) at $2.4 million and Wellesley Hills (No. 93) at $2.3 million.

Generally, coastal ZIP codes performed well, researchers noted.

“As always, the country’s leading zip codes were characterized by coastal proximity,” said PropertyShark senior writer Eliza Theiss. “Of the 122 zips making up the top 100 (the result of multiple price ties), 72 are located within five miles of the coast and 39% are less than one mile away. In fact, only five locations are more than 25 miles from the ocean.”